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# If the variables w,x,y and z are chosen at random so that
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If the variables w,x,y and z are chosen at random so that each variable is a distinct element of the set {-2,-1,0,1}, what is the probability that the product w(x+1)(y-1)(z+2) is not equal to 0?
(A) 1/4 (B) 7/24 (C) 1/3 (D) 3/8 (E) 5/12
Last edited by kevincan on 20 Apr 2007, 09:14, edited 1 time in total.
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Joined: 08 May 2006
Posts: 24
### Show Tags
20 Apr 2007, 08:42
Does "distinct" mean that w,x,y,z must be different?
If so I still get a different answer to those listed: 15/24
24 possible outcomes of which 15 have either w =0, x=-1,y =1 or z =2.
Can anyone else get the right answer and show technique?
Thanks.
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Posts: 1262
### Show Tags
20 Apr 2007, 09:15
doc14 wrote:
Does "distinct" mean that w,x,y,z must be different?
If so I still get a different answer to those listed: 15/24
24 possible outcomes of which 15 have either w =0, x=-1,y =1 or z =2.
Can anyone else get the right answer and show technique?
Thanks.
You're right! The question has been corrected.
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Joined: 30 Nov 2006
Posts: 591
Location: Kuwait
### Show Tags
20 Apr 2007, 09:19
How many ways can we arrange the elements of the set over the four variabes = 4! = 4x3x2x1 = 24
The cases when the equation would equal zero is:
w = 0 --> 6 ways
x = -1 --> 5 ways
y = +1 --> 3 ways
z = -2 --> 2 ways
Sum: 16 ways
Probability that the equation equals zero = 16/24 = 2/3
Probability that the equation does NOT equal zero = 1 - 2/3 = 1/3
What is OA ?
Last edited by Mishari on 20 Apr 2007, 11:26, edited 1 time in total.
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### Show Tags
20 Apr 2007, 10:03
Total combinations = 4! = 24
For the product to be zero, w = 0 or x = -1, y = 1 , z = -2
w = 0 , number of cases = 6
x = -1, number of cases = 6-2= 4(as 2 cases already counted in w = 0)
y =1 , number of cases = 6-2 -1 = 3 (as 2 cases already counted in w = 0 and 1 case already counted in x=-1)
z = -2 , number of cases = 1
Number of cases when product will be zero = 14
Probability of product to be zero = 14/24 = 7/12
Probability of product not to be zero = 5/12
VP
Joined: 08 Jun 2005
Posts: 1145
### Show Tags
20 Apr 2007, 10:06
hi
Total - 4! = 24
Probability mass function
for k(from 1 to n) = C(n,k)*(n-k)!*(-1^k-1)
k=1 C(4,1)*3!*1 = 4*6*1 = 24
k=2 C(4,2)*2!*-1 = 6*2*-1 = -12
k=3 C(4,3)*1!*2 = 4*1*1 = 4
k=4 = 0
24-12+4 = 16
the Probability that equation equal 0 is: 16/24 = 2/3
the Probability that equation not equal 0 is: 1 - 2/3 = 1/3
http://en.wikipedia.org/wiki/Binomial_distribution
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Joined: 28 Feb 2007
Posts: 197
Location: California
Re: PS: Product of 0 [#permalink]
### Show Tags
20 Apr 2007, 19:15
kevincan wrote:
If the variables w,x,y and z are chosen at random so that each variable is a distinct element of the set {-2,-1,0,1}, what is the probability that the product w(x+1)(y-1)(z+2) is not equal to 0?
(A) 1/4 (B) 7/24 (C) 1/3 (D) 3/8 (E) 5/12
I got the C as answer. but my method was clumsy. anyone got any insights?
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Re: PS: Product of 0 [#permalink]
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21 Apr 2007, 00:51
kevincan wrote:
If the variables w,x,y and z are chosen at random so that each variable is a distinct element of the set {-2,-1,0,1}, what is the probability that the product w(x+1)(y-1)(z+2) is not equal to 0?
(A) 1/4 (B) 7/24 (C) 1/3 (D) 3/8 (E) 5/12
(w,x,y,z) must be a permutation of {-2,-1,0,1}. There are 4!=24 equally probable permutations.
For the product not to equal 0, w must not be 0, x must not be -1, y must not be 1 and z must not be -2.
w=-1, x=0, y=-2,z=1
w=-1, x=1, y=-2, x=0
w=-1, x=-2, y=0, x=1
w=1, x=0, y=-2, z=-1
w=1, x=-2, y=0, z=-1
w=1, x=-2, y=-1, z=0
w=-2,x=0,y=1,z=-1
w=-2,x=1,y=0,z=-1
w=-2,x=-2,y=0,z=1
So probability is 9/24= 3/8
We can think this way, w can be any of three numbers. For each possibility of w, consider the variable whose value has been taken by w. It can assume any of the 3 values left
Re: PS: Product of 0 [#permalink] 21 Apr 2007, 00:51
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http://www.askphysics.com/tag/force-of-gravity/
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Home » Posts tagged 'force of gravity'
# Tag Archives: force of gravity
## Gravity on moon
We know that the first man to walk on moon was Neil Armstrong. it is said that there is no force of gravity on moon. then how did Neil Armstrong moved a few steps on moon?
Who says there is no gravity in moon?
The acceleration due to gravity on moon is 1/6 that on earth.
I feel that you are confused by the concept of weightlessness in satellites.
On moon, it has its own gravity which is one sixth that on earth.
## Is linear momentum conserved when a ball is thrown vertically up in the sky?
ROUNAK BHATTACHARJEE asked the above question.
The fact is that linear momentum is conserved in all interactions. If you concentrate on the motion of a single body alone, that will not account for an interaction. When thrown above, according to the principle of conservation of momentum, what we can say is that “The total momentum of the ball plus the thrower just before throwing is equal to the total momentum just after throwing”
After that what happens is controlled by the force of gravity acting on it. The force acting on it can change the momentum. Here the interaction is between the ball and the earth. On account of the huge mass of earth, the motion of earth to compensate the motion of ball and to conserve the momentum cannot be detected.
However, the linear momentum is conserved in all events and interactions so far!
## Effect of Relativity on Gravitation
I wonder, If we take atoms travelling with speeds close to that of light, there will be an increase in mass (according to the theory of [wiki]relativity[/wiki]). As the mass increases, the gravitational force should also increase. Will this increase in [wiki]gravity [/wiki]affect the surrounding space?
If an atoms travels with 99% the speed of light, what will be its increase in mass?
(The question was reformatted to suit the language)
I must congratulate you first for thinking deep and differently.
The relativistic increase in mass is given by the equation $m=\frac{m_{0}}{\sqrt{1-\frac{v^{2}}{c^{2}}}}$
The increase in mass increases the gravity, but the force of gravity is governed by the value of the universal constant of gravitaton, which is very low (6.67 x 10-11).
For the second part of your question, the increase in mass can be calculated to be about 7 times from the equation mentioned above.
(Please post your further doubts on this topic as comment to this post so that all related ideas come together.)
### Hits so far @ AskPhysics
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| 2021-09-28T04:45:01 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"Home » Posts tagged 'force of gravity'
# Tag Archives: force of gravity
## Gravity on moon
We know that the first man to walk on moon was Neil Armstrong. it is said that there is no force of gravity on moon. then how did Neil Armstrong moved a few steps on moon?
Who says there is no gravity in moon?
The acceleration due to gravity on moon is 1/6 that on earth.
I feel that you are confused by the concept of weightlessness in satellites.
On moon, it has its own gravity which is one sixth that on earth.
## Is linear momentum conserved when a ball is thrown vertically up in the sky?
ROUNAK BHATTACHARJEE asked the above question.
The fact is that linear momentum is conserved in all interactions. If you concentrate on the motion of a single body alone, that will not account for an interaction. When thrown above, according to the principle of conservation of momentum, what we can say is that “The total momentum of the ball plus the thrower just before throwing is equal to the total"
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"Home » Posts tagged 'force of gravity'
# Tag Archives: force of gravity
## Gravity on moon
We know that the first man to walk on moon was Neil Armstrong. it is said that there is no force of gravity on moon. then how did Neil Armstrong moved a few steps on moon?
Who says there is no gravity in moon?
The acceleration due to gravity on moon is 1/6 that on earth.
I feel that you are confused by the concept of weightlessness in satellites.
On moon, it has its own gravity which is one sixth that on earth.
## Is linear momentum conserved when a ball is thrown vertically up in the sky?
ROUNAK BHATTACHARJEE asked the above question.
The fact is that linear momentum is conserved in all interactions. If you concentrate on the motion of a single body alone, that will not account for an interaction. When thrown above, according to the principle of conservation of momentum, what we can say is that “The total momentum of the ball plus the thrower just before throwing is equal to the total"
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https://astronomy.stackexchange.com/questions/40919/if-an-orbit-is-shifting-due-to-orbital-precession-is-it-still-a-keplerian-orbit?noredirect=1
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# If an orbit is shifting due to orbital precession, is it still a Keplerian orbit?
I was thinking about orbits a few days ago, and realized that orbits shift/precess naturally. Given that a two-body problem with a star and a planet, if the planet has an eccentric orbit that precesses, would we still call it a Keplerian orbit?
• There is no such thing in nature as a Keplerian orbit. The concept remains useful because (a) many orbits are approximately Keplerian, and (b) the deviations from a true Keplerian orbit can be modeled rather nicely in terms of things like a precession rate. Jan 18 at 10:40
• Kepler is a first approximation. In the real world you need to add virial coefficients: en.wikipedia.org/wiki/Virial_coefficient It gets ugly. Feb 7 at 17:15
No orbits are strictly Keplerian, unless you really monkey about with your coordinate systems. However, a precessing orbit is pretty darned Keplerian.
The relationship between the various orbital elements can be a little complicated, and precession is traditionally thought of as the rotation of the periapsis of the orbit around the more massive body. If we look at the orbital elements, we can think of it instead as a changing term to the longitude of the ascending node. So we could capture the longitude of the ascending node, $$\Omega_0$$ at some initial time $$t_0$$. Then, at any time t, the longitude of the ascending node would be $$\Omega=\Omega_0+(t-t_0)\omega_p$$, where $$\omega_p$$ is the rate of precession. The rest of the orbital elements can be treated as constant.
• Love the diagram! +1 Why is a binary star system not d̶a̶r̶n̶e̶d̶ Keplerian even though they are just 2 bodies with e<1? Jan 18 at 19:05
• @fasterthanlight A binary star system is just a little Keplerian because Kepler didn't know about the barycenter. Kepler would have had a hard time rectifying the movement of both bodies around an empty focus of an ellipse. Of course, which orbit goes in which column is highly subjective. Jan 18 at 22:33
• as soon as I saw "monkey about with your coordinate systems" I knew who the author was going to be :-)
– uhoh
Feb 6 at 5:37
• @uhoh Guilty as charged! I can't resist a good orbit or coordinate system question! Feb 6 at 20:10
Strictly speaking, pure Keplerian orbits can only occur with two bodies obeying Newton's law of gravitation. If there are more than two bodies then the orbits will be perturbed, to some degree.
Kepler orbits are a reasonable first approximation to the orbits of the planets in the Solar System because the Sun is so massive compared to the planets, and the distances between the planets are relatively large, so the planets don't perturb each other's orbits very much. In units of $$10^{-6}$$ solar masses, the masses of the larger planets are approximately:
Planet Mass
Jupiter 954.8
Saturn 285.9
Uranus 43.66
Neptune 51.51
The Earth-Moon system weighs in at around 3.04.
Kepler was fortunate that he had sufficiently accurate data to see the patterns that led to his 3 laws of planetary motion, but not so accurate that he could see those laws were only a rough approximation. ;) Fortunately, Newton came along a few decades later and showed how Kepler's laws were a consequence of the laws of mechanics and gravitation applied to two bodies. However, Newton also realised that the Moon's orbit around the Earth was significantly perturbed by the Sun. In fact, the Moon's motion is quite complex and its orbit precesses in various ways on rather short time scales.
This complexity is (mostly) because the Moon's mass is quite large relative to the mass of the Earth, so the Earth-Moon barycentre is a significant distance from the centre of the Earth (on average 4,671 km or 0.75 of the Earth's radius). So the Moon's orbit is not well-approximated by an ellipse with the centre of the Earth at one focus. Also, most moons have orbits that are close to their primary's equatorial plane, but the Moon's orbital plane is near the ecliptic plane (with a mean inclination ~5.1°), like a planet's orbit. If the Moon had a small mass it probably would have been pulled into an equatorial orbit long ago. The torque caused by the Earth trying to pull the Moon into an equatorial orbit causes the nodal precession.
Under Newton's laws, it's impossible for the orbit of a perfectly spherical single planet (without moons) orbiting a perfectly spherical single star to precess. The only possible (closed) orbits are nice Keplerian ellipses (including circles), with a fixed orientation and eccentricity. To be precise, the star and planet will move in complementary elliptical trajectories around their barycentre, always remaining in the same plane, and collinear with the barycentre. If the bodies aren't perfect spheres, with spherically symmetric density profiles, then they cannot be modelled as points via the Shell theorem and nodal precession is possible.
However, under the laws of General Relativity, such a planet with non-zero eccentricity must precess (and the greater the eccentricity, the greater the rate of precession), but the amount of precession is very small unless the star is very massive. Mercury's orbit precesses by about 532 arc-seconds per century, Newtonian gravity accounts for all but 43 of those arc-seconds.
• "because the Moon's mass is relatively large for a satellite its motion is quite complex and its orbit precesses in various ways on rather short time scales." Wouldn't apsidal and nodal precession take place at nearly the same rate even if the Moon were 100x smaller? There could be a difference of a percent or so due to center-of-mass shift, but I don't see why these are otherwise related to the mass of the Moon. Cool table formatting btw :-)
– uhoh
Feb 6 at 23:02
• @uhoh Fair points. However, if the Moon's mass were small then it would have been pulled into an equatorial orbit fairly quickly, so the nodal precession would be much smaller. I think the apsidal precession would be much smaller if the Earth-Moon barycentre were closer to the centre of the Earth, but I'd need to calculate (or simulate) that to be certain. ;) Feb 7 at 5:00
• This is very interesting, the first apsidal precession equations we can find are for a massless particle in a central field, I don't know how they are modified for two more equivalent bodies orbiting a barycenter. But why then would a smaller moon be pulled into an equatorial orbit fairly quickly? All gravitational accelerations of the center of mass of body are independent of the body's mass. Perhaps I can ask this as a new question? "Does the equatorialization rate of inclinded Moons depend on the Moon's mass?"
– uhoh
Feb 7 at 5:28
• I'd like to see a reference or mathematical treatment, I'm not good at prose explanations, they don't necessarily obey conservation laws. If I asked that proposed title as a question could you author a well-supported SE answer to it?
– uhoh
Feb 7 at 5:39
• Feb 7 at 9:02
It depends how you define 'Keplerian orbit'. A precessing orbit can obviously not be represented by a stationary ellipse anymore, but it is essentially still the same ellipse, merely uniformly rotating about its focus. The main features of the orbit, like semi-major axis and period of revolution (as defined by the time interval between two perihelion passages) are still the same. So Kepler's laws still apply if interpreted in this sense. If you go to the Horizons Website you can check for yourself that the planetary ephemerides are still calculated on the basis of Kepler's laws (although, since there are more than 2 bodies involved, the orbital elements vary with time and are only treated as 'osculating' elements).
| 2021-10-23T17:54:17 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# If an orbit is shifting due to orbital precession, is it still a Keplerian orbit?
I was thinking about orbits a few days ago, and realized that orbits shift/precess naturally. Given that a two-body problem with a star and a planet, if the planet has an eccentric orbit that precesses, would we still call it a Keplerian orbit?
• There is no such thing in nature as a Keplerian orbit. The concept remains useful because (a) many orbits are approximately Keplerian, and (b) the deviations from a true Keplerian orbit can be modeled rather nicely in terms of things like a precession rate. Jan 18 at 10:40
• Kepler is a first approximation. In the real world you need to add virial coefficients: en.wikipedia.org/wiki/Virial_coefficient It gets ugly. Feb 7 at 17:15
No orbits are strictly Keplerian, unless you really monkey about with your coordinate systems. However, a precessing orbit is pretty darned Keplerian.
The relationship between the various orbital elements can be a little complicate"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# If an orbit is shifting due to orbital precession, is it still a Keplerian orbit?
I was thinking about orbits a few days ago, and realized that orbits shift/precess naturally. Given that a two-body problem with a star and a planet, if the planet has an eccentric orbit that precesses, would we still call it a Keplerian orbit?
• There is no such thing in nature as a Keplerian orbit. The concept remains useful because (a) many orbits are approximately Keplerian, and (b) the deviations from a true Keplerian orbit can be modeled rather nicely in terms of things like a precession rate. Jan 18 at 10:40
• Kepler is a first approximation. In the real world you need to add virial coefficients: en.wikipedia.org/wiki/Virial_coefficient It gets ugly. Feb 7 at 17:15
No orbits are strictly Keplerian, unless you really monkey about with your coordinate systems. However, a precessing orbit is pretty darned Keplerian.
The relationship between the various orbital elements can be a little complicate"
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https://cs.stackexchange.com/questions/55432/confusion-in-bankers-algorithm-how-resources-are-allocated
|
# Confusion in Banker's Algorithm: How resources are allocated?
I have seen examples about Banker's Algorithm from this Wikipedia link, this book and many other places. In all these examples some processes are allocated resources less than their Max Need.
For example, consider the state of system as shown in below given image taken from Wikipedia link:
Here you can see that the process P1's Max Need is 3 3 2 2 and the total available resources are 6 5 7 6. But the system allocates 1 2 2 1 resources to P1. Although it could allocate all the requested resources to P1 and P1 would have completed.
So my questions are:
• Why does the system allocate partial / incomplete resources even when it has the resources available
• If the allocation of partial / incomplete resources is allowed, then why does the system / algorithm enforce that the number of requested / needed resources should be less than the available resources (at the time of request)?. The system could allocate some resources (available at the time of request) to process(es) and the remaining would have been assigned when released by other processes.
OR
The process has to tell the number of resource types (and their instances) in advance, but does not need to be assigned all resources at a time; rather it is assigned resources when actually needed?
Please correct me if I am wrong.
• We expect references to fulfill the minimal scholarly requirements and be as robust over time as possible. Please take some time to improve your post in this regard. We have collected some advice here. – Raphael Apr 10 '16 at 17:31
• a major design criteria of this algorithm seems to be to (provably) avoid deadlocks (due to lack of resources), and therefore the allocation logic must know the most resources that will ever be requested to fulfill the proof. ofc there are zillions of algorithms for resource allocation and others may be more apropriate for some situations. other algorithms may better mesh with some of the different scenarios youre asking about. if you look into the proof of how the algorithm avoids deadlock you will likely find the conditions as requirements of the proof & can understand better the design. – vzn Apr 10 '16 at 22:11
| 2020-10-30T01:46:55 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Confusion in Banker's Algorithm: How resources are allocated?
I have seen examples about Banker's Algorithm from this Wikipedia link, this book and many other places. In all these examples some processes are allocated resources less than their Max Need.
For example, consider the state of system as shown in below given image taken from Wikipedia link:
Here you can see that the process P1's Max Need is 3 3 2 2 and the total available resources are 6 5 7 6. But the system allocates 1 2 2 1 resources to P1. Although it could allocate all the requested resources to P1 and P1 would have completed.
So my questions are:
• Why does the system allocate partial / incomplete resources even when it has the resources available
• If the allocation of partial / incomplete resources is allowed, then why does the system / algorithm enforce that the number of requested / needed resources should be less than the available resources (at the time of request)?. The system could allocate some resources"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Here's an extract from a webpage:
"# Confusion in Banker's Algorithm: How resources are allocated?
I have seen examples about Banker's Algorithm from this Wikipedia link, this book and many other places. In all these examples some processes are allocated resources less than their Max Need.
For example, consider the state of system as shown in below given image taken from Wikipedia link:
Here you can see that the process P1's Max Need is 3 3 2 2 and the total available resources are 6 5 7 6. But the system allocates 1 2 2 1 resources to P1. Although it could allocate all the requested resources to P1 and P1 would have completed.
So my questions are:
• Why does the system allocate partial / incomplete resources even when it has the resources available
• If the allocation of partial / incomplete resources is allowed, then why does the system / algorithm enforce that the number of requested / needed resources should be less than the available resources (at the time of request)?. The system could allocate some resources"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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https://stats.stackexchange.com/questions/407857/two-logistic-regression-or-one-softmax-regression
|
Two logistic regression or one Softmax regression
The following question is from Geron's Hans-On Machine Learning book.
Suppose you want to classify pictures as outdoor/indoor and daytime/nighttime. Should you use two Logistic regression or one Softmax regression classifier?
The answer the books gives is that
Need to use two Logistic Regression classifiers since these are not exclusive classes (i.e. all four combinations are possible).
However, the part I don't understand is that we can make them into following four exclusive classes:
1. Daytime and Outdoor
2. Nighttime and Outdoor
3. Daytime and Indoor
4. Nighttime and Indoor This way we still cannot use Softmax regression classifier?
Thanks!
If your case was to classify the image as either outdoor, indoor, daytime, nighttime; you'd use softmax. They're now exclusive because any two cannot occur at the same time. But in the original question, a photo can be both daytime and indoor, for example. You should use one logistic regression for each binary classification problem.
If you make four exclusive classes like you listed, then you can certainly use softmax, i.e. last layer of your neural net will contain four neurons responsible for each newly defined class.
I'll answer your question by highlighting a problem which could occur quite often if you use a softmax classifier.
In this case, the output of softmax will be a vector of 4 probabilities in decreasing order. The interpretation of the softmax output is that for a well performing model, the topmost probabilities are the ones that are most likely to be true.
But if you mix together two different phenomenon which are not mutually exclusive, then this interpretation will not be correct.
For example, you could get an output like: Indoor=0.9, Outdoor=0.65, Night=0.35, Day=0.20. If you want to circumvent this problem, an extra logic would need to be applied to this output to re-interpret the two different requirements - Day/Night vs. Indoor/Outdoor.
In case training two classifiers is extremely costly in terms of time/effort then such an approach may still be justified.
The answer is not clear because 2*2=2+2. I’ll explain. Suppose that you had third dimension winter/summer. In this case for soft max you’d need 8 classes, while with logistics it’s only 6 states in total, I.e. $$2\times 3$$vs. $$2^3$$. That’s what he means by non exclusive.
The problem is inherently non exclusive, and if you try yo model it as if it was exclusive you’ll be wasting a lot of resources when the number of dimensions is large. Imagine it’s 20 different binary features. Soft max would have to deal with 1 million states!
| 2020-01-23T13:12:45 |
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"url": "https://stats.stackexchange.com/questions/407857/two-logistic-regression-or-one-softmax-regression",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"Two logistic regression or one Softmax regression
The following question is from Geron's Hans-On Machine Learning book.
Suppose you want to classify pictures as outdoor/indoor and daytime/nighttime. Should you use two Logistic regression or one Softmax regression classifier?
The answer the books gives is that
Need to use two Logistic Regression classifiers since these are not exclusive classes (i.e. all four combinations are possible).
However, the part I don't understand is that we can make them into following four exclusive classes:
1. Daytime and Outdoor
2. Nighttime and Outdoor
3. Daytime and Indoor
4. Nighttime and Indoor This way we still cannot use Softmax regression classifier?
Thanks!
If your case was to classify the image as either outdoor, indoor, daytime, nighttime; you'd use softmax. They're now exclusive because any two cannot occur at the same time. But in the original question, a photo can be both daytime and indoor, for example. You should use one logistic regr"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Two logistic regression or one Softmax regression
The following question is from Geron's Hans-On Machine Learning book.
Suppose you want to classify pictures as outdoor/indoor and daytime/nighttime. Should you use two Logistic regression or one Softmax regression classifier?
The answer the books gives is that
Need to use two Logistic Regression classifiers since these are not exclusive classes (i.e. all four combinations are possible).
However, the part I don't understand is that we can make them into following four exclusive classes:
1. Daytime and Outdoor
2. Nighttime and Outdoor
3. Daytime and Indoor
4. Nighttime and Indoor This way we still cannot use Softmax regression classifier?
Thanks!
If your case was to classify the image as either outdoor, indoor, daytime, nighttime; you'd use softmax. They're now exclusive because any two cannot occur at the same time. But in the original question, a photo can be both daytime and indoor, for example. You should use one logistic regr"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://physics.stackexchange.com/questions/443202/rutherford-gold-experiment/443210
|
Rutherford gold experiment
When an alpha particle is nearing the gold atoms nucleus, it is slowing down due to electrostatic repulsion, right? But then why is the acceleration or velocity not a minimum at that point (the point where the alpha particle reverses its direction)and why is the speed a minimum? Like isn't the resultant force on the alpha particle reducing which should cause its acceleration to be minimum?
When something changes direction, the velocity vector changes direction. Therefore, at the point of changing directions the velocity is $$0$$.
| 2019-12-09T02:45:51 |
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"url": "https://physics.stackexchange.com/questions/443202/rutherford-gold-experiment/443210",
"openwebmath_score": 0.8199732899665833,
"openwebmath_perplexity": 505.8916835491746,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672227971211,
"lm_q2_score": 0.6187804267137442,
"lm_q1q2_score": 0.5000161809357928
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Rutherford gold experiment
When an alpha particle is nearing the gold atoms nucleus, it is slowing down due to electrostatic repulsion, right? But then why is the acceleration or velocity not a minimum at that point (the point where the alpha particle reverses its direction)and why is the speed a minimum? Like isn't the resultant force on the alpha particle reducing which should cause its acceleration to be minimum?
When something changes direction, the velocity vector changes direction. Therefore, at the point of changing directions the velocity is $$0$$."
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Rutherford gold experiment
When an alpha particle is nearing the gold atoms nucleus, it is slowing down due to electrostatic repulsion, right? But then why is the acceleration or velocity not a minimum at that point (the point where the alpha particle reverses its direction)and why is the speed a minimum? Like isn't the resultant force on the alpha particle reducing which should cause its acceleration to be minimum?
When something changes direction, the velocity vector changes direction. Therefore, at the point of changing directions the velocity is $$0$$."
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://ecom.arq.br/etkn/gv8hp.php?px=xor-gate-using-nor-gate
|
# Xor Gate Using Nor Gate
It will only output power when one input is on, so it doesn't have the issue with the XNOR gate where you have to be able to supply power when both switches are off, and it will still make it so that toggling either of the switches will toggle the output of the XOR gate. A NOR gate made out of transistors. Today we are going to discuss Truth Table, Internal circuit and Symbol of XOR Gate. As I mentioned in Mechanic NOR gate I was working on extending the NOR-gate to a compact XOR-gate and I finally succeeded in making a prototype of it. The XOR gate is a digital logic gate that implements an exclusive or; that is, a true output (1) results if one, and only one, of the inputs to the gate is true (1). Introduction to XOR Gate. NOR gate is used in combination to perform the AND, OR and Inverter operations. Half Adder using only the NOR gate. All-optical XOR, NOR, and NAND gates are realized using two parallel SOA-MZIs. If only one of the inputs is 1 (or TRUE) then the output is 1. Leakage Currents 12. An XOR gate implements an exclusive or; that is, a true output results if one, and only one, of the inputs to the gate is true. (Apologies for the quality of images) Using NAND Gate. They are the basic building blocks of any digital system. Online logic gate calculator to calculate AND, OR, XOR, NAND, NOT, NOR and XNOR gate values. And in the rust implementation, you also need 2 splitters and 2 blockers with a power source to each blocker. This monostable is built around 2 LOGIC gates. Figure 9 – NOR gate. If they are, the output is 1. The structure used for all the three gates is the same and according to the input selection, the desired gate is created. The more than two input terminals XOR Gate also available. The OR gate has its own symbol. Out of the seven logic gates discussed above, NAND and NOR are also known as universal gates since they can be used to implement any digital circuit without using any other gate. vhdl program for nand gate; vhdl program for not gate; vhdl program for nor gate; vhdl program for or gate; vhdl program for sr flip flop; vhdl program for xnor gate; vhdl program for xor gate; cryptography & network security unit 7 notes; fpga previous papers; computer organization previoua papers; optical communications notes; micro wave. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. When logic gate is selected , corresponding led start glowing. Each output and output of a logic gate is represented by binary conditions 0 (LOW) and 1 (HIGH). People refer to a AND gate followed by a NOT as a NAND (Not-AND). This page on AND vs NAND vs OR vs NOR gates mentions truth table and logic symbols of AND,NAND,OR and NOR gate. This means that every gate can be created by NAND or NOR gates only. 2-input XOR gate using 2x1 mux: Figure 11 shows the truth table for a 2-input XOR gate. These basic digital logic gates that is AND, OR and NOT gates can be combined together in particular topologies to realize other important gates. The cmos type of switches have two gates and so have two control signals. An alternative arrangement of five NOR gates is shown below, in a topology that emphasizes the construction of the function from (noting from de Morgan's Law that a NOR gate is, in effect, an inverted-input AND gate) but this is clearly not as versatile a 5-gate construction of the XOR function as the one derived from the XNOR construction. This chip includes 4 basic digital logic NAND gates. You can't have AND gate using XOR gate! You can only get buffer or inverter! To be an universal gate a gate needs to satisfy both the following conditions! 1. fig 4 NOR AS NAND A NAND gate is made using an AND gate in series with a NOT gate. Find false value in XOR operations. Th resistance is inversely proportional to the W/L ratio can be illustrated using Pspice simulation. The XOR of a and b is a function equal. You should be able to get inverter using the gate. Model Library. I will publish all these in coming blog posts along with the elaborated figures. The NAND and NOR gates are called universal gates. Simple OR gates take 2 inputs and determine if either one of them is a 1 or both. Logic Gates are basic building blocks in Digital Electronics. Draw the symbols for the NAND, NOR, XOR, and XNOR gates. Without logic gates, electronic world would be nearly incomplete! 19 Bibliography. For example an AND gate is a gate that outputs 1 when all its inputs are 1, an OR gate outputs 1 when any of the inputs is 1, a NAND gate outputs 0 when all its inputs are 1, a NOR gate outputs 1 when all its inputs are 0. Skip to main content. Fill out the observation pages. com/electronixhub1. Out of the seven logic gates discussed above, NAND and NOR are also known as universal gates since they can be used to implement any digital circuit without using any other gate. of arbitrary digital gates such as NOR, NAND and XOR. it does a logic operation on one or more bits of input and gives a bit as an output. 0 which you can find out from the truth table of the NOR gate. Minimum number of NAND gates required to implement full adder is 9. XOR from NOR. Several kinds of digital logic circuits are the basic elements that. Popular Interview question on internet. An EX-OR gate can be designed by using basic logic gates like NAND gate and NOR gate. Leakage Currents 12. The output of an XOR gate is true only when exactly one of its inputs is true. It has n input (n >= 2) and one. Xor gate transistor diagram. Convert all OR gates to NAND gates with invert-OR symbols 3. Other types of gates. Help on CMOS 3-input XOR gate Example- CD4001 is a chip with NOR gates. Many circuits have been. AND and OR are not parity functions. An XOR gate implements an exclusive or ; that is, a true output results if one, and only one, of the inputs to the gate is true. Using the circle symbols for inverting the inputs is another way to show the OR gate. Replacing gates in a boolean circuit with NAND and NOR. 1: 2-input XOR gate using only NAND gates. Digital circuits are more frequently constructed with NAND or NOR gates than with AND and OR gates. Theory: AND, OR, NOT are called basic gates as their logical operation cannot be simplified further. The Ex-NOR function is a combination of different basic logic gates Ex-OR and a NOT gate, and by using the 2-input truth table above, we can expand the Ex-NOR function to: which means we can realise this new expression using the following individual gates. Similar concept can be applied to create all basic gates from 2:1 MUX. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0. Making an XNOR Gate. An XOR Gate is a Logic Gate that has two or more than two Inputs, its Output is 1 only when exactly one of its Inputs is 1. fig 4 NOR AS NAND A NAND gate is made using an AND gate in series with a NOT gate. Figure 6: Realization of the XOR gate in terms of AND and OR gates. In construction, you can see that this is similar to the AND gate: (in fact, the AND gate is actually a combination of a NAND plus a NOT). Popular Interview question on internet. $(A + B)(A + B’)$. To re-design this system using NAND gates only begin by replacing each gate with its NAND gate equivalent, as shown below: Then simplify the system by deleting adjacent pairs of NOT gates (marked X above). These four gate are connected internally as shown in below figure. If we observe carefully, OUT equals B when A is '0' and B' when A is '1'. Check the circuit for NOR to inverter (equivalent of NAND to inverter). Half Adder using only the NOR gate. Text: Dual 4-Input OR Gate Triple 3-Input OR Gate Similar Devices 4071 7432 XOR Gates Device 7486 , 7476 7483 7485 7486 7490 7493 74121 2 of 12 Function Quad 2-Input NAND Gate Quad 2 , -Bit Magnitude Comparator Quad 2-Input XOR Gate Decade Counter 4-Bit Binary Counter Monostable Multivibrator , -Input NOR Gate Quad 2-Input XOR Gate Octal D-Type. Implement the AND chip circuit show in Figure 14. Browse our extensive product range below and use the search filters on the left to narrow down your options by brand, logic function and more. Neural Representation of AND, OR, NOT, XOR and XNOR Logic Gates (Perceptron Algorithm) we can conclude that the model to achieve a NOR gate, using the Perceptron algorithm is;-x1-x2+0. They are in vector format, made using PowerPoint's built in vector shape tools, and so they can be formatted as required. 1: 2-input XOR gate using only NAND gates. There are six different switch primitives (transistor models) used in Verilog, nmos, pmos and cmos and the corresponding three resistive versions rnmos, rpmos and rcmos. XOR gate is a logic gate Which can have two or more inputs. XNOR/XOR/NOT. NAND, NOR, EX-OR and EX-NOR Gate. This was the most difficult gate to build, mainly because it is a composite gate made from two ANDs, two NOTs and an OR gate. Class 11: Transmission Gates, Latches Topics: 1. Modify the circuit from question 2to use a second AND gate on the chip. 4T XOR gate to increase circuit density [11] [12]. Related faq OR gate using MUX NAND gate using MUX NOR gate using MUX XOR gate using MUX. An XOR gate circuit can be made from four NAND gates. Another variation is a Exclusive NOR that differs only with an inverted output. Drive XOR from NAND gates. Understanding of the truth table of NOR gate is important before knowing the working of the circuit. If the four NAND gates are replaced by NOR gates, this results in an XNOR gate, which can be converted to an XOR gate by inverting the. Fig6: XNOR gate using QCA majority gate and inverter (a)circuit diagram (b)layout Observing carefully, we can see that the basic layout of XOR and XNOR gates are same. Basically the "Exclusive-NOR" gate is a combination of the Exclusive-OR gate and the NOT gate but has a truth table similar to the standard NOR gate in that it has an output that is normally at logic level "1" and goes "LOW" to logic level "0" when ANY of its inputs are at logic level "1". We won't worry about what the switches would look like for the new rules below… we would have to make our simplified model of an electric circuit more complex to see how they work. The same circuit that was built in the post "Circuit to understand working of and gate"can be made to work as a xor gate too, just by modifying the program. Activity: CMOS Logic Circuits, Transmission Gate XOR Objective: The objective of this lab activity is to reinforce the basic principles of CMOS logic from the previous lab activity titled "Build CMOS Logic Functions Using CD4007 Array"[1] and gain additional experience with complex CMOS gates. The concept of NAND gate, NOR gate, Universal gate, Boolean functions, logic circuits or networks are explained briefly. For example, just a simple diagram with an or gate is like the follow. Meaning of xor gate. Using these three basic gates we can also construct four more Gates - NAND Gate, NOR Gate, XOR Gate & XNOR Gate. Help on CMOS 3-input XOR gate Example- CD4001 is a chip with NOR gates. digital design entry level interview questions for asic fpga verification. Their trip points are specified with instance parameters Vt and Vh. XOR Gate using Basic logic gates If a specific gate is not available directly, we will design that gate by using multiple gates. The XOR gate produces a logic 1 output only if its two inputs are different. As can be seen in the logic diagram below, the XOR gate is built by combining three more simple gates, the OR gate, the NAND gate and the AND gate to produce the desired result. Figure 1 below shows the implementation of XOR gate using 2-input NAND gates. Related icons include landmark icons, door icons, building icons, entrance icons, architecture icons. The more than two input terminals XOR Gate also available. Image info : Resolution:600x445 Size:12kB. The XOR gate produces a logic 1 output only if its two inputs are different. So I figured out how to make a XOR logic gate using doors. I have explained in detail, the working of BICMOS NAND GATE. fig 5 NOR AS XOR An XOR gate is made by connecting the output of 3 NOR gates (connected as an AND gate) and the output of a NOR gate to the respective inputs of a NOR gate. I would like to know what the process for deriving this would look like. Their trip points are specified with instance parameters Vt and Vh. An XOR gate is a parity generator. I have tried but I have to use additional NOT gate to make an XOR gate. Each output and output of a logic gate is represented by binary conditions 0 (LOW) and 1 (HIGH). Created on: 7 December 2012. How To Construct Cmos Equivalent Of An Xnor Gate Using And. Implementation of NAND gate using NOR NOR Construction 14. XOR from NAND logic, NAND to XOR conversion, equations, circuit, minimizatio Truth tables. The cmos type of switches have two gates and so have two control signals. That is why, NAND and NOR gates are called the Universal gates. jpg File:NOR XOR. The schematic of proposed gate has. CMOS X-Gates 9. Text: Dual 4-Input OR Gate Triple 3-Input OR Gate Similar Devices 4071 7432 XOR Gates Device 7486 , 7476 7483 7485 7486 7490 7493 74121 2 of 12 Function Quad 2-Input NAND Gate Quad 2 , -Bit Magnitude Comparator Quad 2-Input XOR Gate Decade Counter 4-Bit Binary Counter Monostable Multivibrator , -Input NOR Gate Quad 2-Input XOR Gate Octal D-Type. Logic gates - AND, OR, NOT, NOR, NAND, XOR, XNOR Gates. The structure used for all the three gates is the same and according to the input selection, the desired gate is created. As we know, the logical equation of a 2-input XOR gate is given as below: Y = A (xor) B = (A' B + A B') Let us take an approach where we consider A and A' as different variables for now (optimizations related to this, if any, will consider. These concepts are very important to grasp theme and theory of advance computer courses offered by several universities. 9 The circuit of Fig. An alternative arrangement of five NOR gates is shown below, in a topology that emphasizes the construction of the function from (noting from de Morgan's Law that a NOR gate is, in effect, an inverted-input AND gate) but this is clearly not as versatile a 5-gate construction of the XOR function as the one derived from the XNOR construction. Universal Gate (NAND & NOR): Universal gate is a gate using which all the basic gates can be designed. By using the binary number system, we can make sense of these numbers. The XOR gate (sometimes EOR gate) is a digital logic gate that implements exclusive disjunction it behaves according to the truth table to the right. Any Boolean expression can be implemented using these three basic logic Gates. A truth table is used to show the logic gate function. Logic Gates, NAND, XOR, NOR, OR & XNOR Logic Gates Logic gates are one of the building blocks of digital circuits, and you can use combinations of them to perform complex electronic operations. Understanding of the truth table of NOR gate is important before knowing the working of the circuit. In this study, the NOT, XOR, and NOR logic gates were designed and simulated using two dimensional photonic crystals. This tutorial covers the remaining gates, namely NAND, NOR, XOR and XNOR gates in VHDL. Label the outputs Y3Y2Y1Y0 and the inputs X3X2X1X0. NOR gate circuit is a logic circuit where output is always zero except when all inputs are zero. NAND, NOR, EX-OR and EX-NOR Gate. source, gate). This current passes through the resistor and causes the appearance of a voltage across its terminals, thereby obtaining logic “1” on the output. How to Build a Diode OR Gate Circuit. NOR is a functionally complete operation because the NOR gates can be combined to generate any other logical function. Truth table is used to show logic gate function. An XNOR gate (sometimes referred to by its extended name, Exclusive NOR gate) is a digital logic gate with two or more inputs and one output that performs logical equality. Realization of Boolean expressions using NAND and NOR. OR and NAND using NOR. xor gate, now I need to construct this gate using only 4 nand gate. Very quickly, below are the symbols, boolean expression and truth table of NAND and NOR gates: Now let us see how each logic gate can be created with NAND and NOR gates. Convert all OR gates to NAND gates with invert-OR symbols 3. A logic gate is a model used to perform boolean operations on several logic inputs to produce a single output. Basically the “Exclusive-NOR” gate is a combination of the Exclusive-OR gate and the NOT gate but has a truth table similar to the standard NOR gate in that it has an output that is normally at logic level “1” and goes “LOW” to logic level “0” when ANY of its inputs are at logic level “1”. They are in vector format, made using PowerPoint's built in vector shape tools, and so they can be formatted as required. The xor gate is high only when one of its inputs is high but not both. An XOR logic gate circuit can be made from four NAND or five NOR logic gates as in the configurations shown below. Now you could ask "why" would you want to go to the trouble of constructing an XOR gate (or any other logic element for that matter) from multiple gates when, in the case of the XOR gate, you could just use a 7486 IC, which is a Quad 2-input XOR IC. Sometimes there is, however, a need for a gate that gives an output when either of the inputs is 1 but not when both are 1, i. These two gates are the digital building blocks. You would use this gate in similar circumstances to the AND gate, where you want to be able to control an outside switch from the inside. Basically, the XOR Gate has two input terminals and one output terminal. The AND gate implementation using three NOR gates is shown in figure 6. It is a one bit. It produces an output pulse, either high or low by using NOR or NAND gates. Thus corresponding to each combination of the inputs of the NOR Gate, it will have an output that is the complement of the output of the OR Gate. This circuit gives a high (1) or true output if even number of high inputs are applied. Starting Cadence Virtuoso Before beginning this tutorial youshould have setup your account to work with Cadence Virtuoso. Due to this property, NAND and NOR gates are sometimes called "universal gates". Logic Gates are basic building blocks in Digital Electronics. Using these three basic gates we can also construct four more Gates – NAND Gate, NOR Gate, XOR Gate & XNOR Gate. Modify the circuit from question 2to use a second AND gate on the chip. It looks as if C OUT may be either an AND or an OR function, depending on the value of A, and S is either an XOR or an XNOR, again depending on the value of A. An XOR gate symbolized as ⊕ in a. As pointed out in previous paragraph that NOR Gate is the combination of OR and NOT Gate with input of NOT Gate connected at the output of the OR Gate. Presentations (PPT, KEY, PDF) logging in or signing up. If we observe carefully, OUT equals B when A is '0' and B' when A is '1'. For practice or experiment using logic gate you can use logic gate made of switch, diode, relay and so on. So, from what I understand: The NAND gate should be receiving power from the generator, in order for it to be able to turn on if its conditions are met. " This type of digital logic gate produces a high output only if two binary results are satisfied by a zero or low input. Minimum number of NAND gates required to implement full adder is 9. Ex-OR gate(XOR) & Ex-NOR using NOR gate (English) - Duration: 12:01. Click the input-switches or type the 'a' and 'b' bindkeys to control the circuit. Fill out the observation pages. if both input is same the output is LOW, the output will below. Simple OR gates take 2 inputs and determine if either one of them is a 1 or both. Popular Interview question on internet. I want to make XOR gate using OR gate. We have already made AND gate, OR gate and inverter using 2:1 MUX. NAND and NOR are called universal gates as using only NAND or only NOR, any logic function can be implemented. This is impossible to implement with XOR gates: in any XOR-only circuit, toggling the second input should either always change the output or never change it. Because of these properties, XOR gates are commonly found in complex redstone circuits. In Boolean expression, the term XOR Read moreXOR Gate | Symbol, Truth table & Circuit. 3 XOR and Ex-NOR gates The XOR is a logical operation on two operands that results in a logical value of true if and only if one of the operands, but not both, has a value of true. It has n input (n >= 2) and one. NOR Gate is the combination of NOT gate at the output of OR gate, hence NOR gate is type of NOT-OR gate. How to use XOR in a sentence. If a redstone signal enters either input side, a redstone signal is emitted on the output side. The above diagram is of an AND gate made from NAND gate. Its output is “true” if the inputs are the same, and”false” if the inputs are different. Page 2 of 2 < Prev 1 2. This system has 3 different gates (NOR, AND and OR) so it requires three ICs, one for each type of gate. Logic gates can be implemented using discrete components such as resistors, diodes, and. This monostable is built around 2 LOGIC gates. NAND and NOR gates are called universal gate because you can construct any gate using NAND gate or NOR gate. NOT Gate: The output of the NOR gate is always opposite of the input , which means that if we give logic 1 at the input of the gate then the output will be logic 0 and vice versa. For practice or experiment using logic gate you can use logic gate made of switch, diode, relay and so on. Starting Cadence Virtuoso Before beginning this tutorial youshould have setup your account to work with Cadence Virtuoso. Understanding of the truth table of NOR gate is important before knowing the working of the circuit. NAND and NOR are universal gates. The XNOR (exclusive-NOR) gate is a combination XOR gate followed by an inverter. The output is on when both input states are different. To derive the rules of Boolean Algebra related to an XOR gate, I take the basic point of standard rules and substitutes the standard rules with an XOR gate function. Nabihah Ahmad, Rezaul Hasan, “A New Design of XOR‐ considered to be the best optimized design of D‐flip flop XNOR gates for low power application”, International based on XOR/XNOR gate with average power = 0. XOR gate directly constructed from MOS transistors. An XOR gate (sometimes referred to by its extended name, Exclusive OR gate) is a digital logic gate with two or more inputs and one output that performs exclusive disjunction. If they are, the output is 1. • Understand how to implement simple circuits based on a schematic diagram using logic gates. com/electronixhub1. An XOR is known as exclusive-OR gate and is almost similar to an OR gate with the only difference that when both the inputs are 1 or True, the output is 0 or False, unlike an OR gate. The XNOR (exclusive-NOR) gate is a combination XOR gate followed by an inverter. Hence we need only 4 NOR GATES to implement XNOR gate and we require 5 NOR gates to implement XOR gate with 5 th NOR gate used as inverter and placed in front of 4 th NOR gate. An XNOR gate is a XOR gate followed by an inverter, and is used in comparator circuits. Everything you need to know about logic gates, the heart and blood of digital electronics. If so, then the output of the gate is 1, else it is 0. If the inputs are the same, the output is a logic 0. Note! For the second NOR gate both the input is equal to R. Out of the seven logic gates discussed above, NAND and NOR are also known as universal gates since they can be used to implement any digital circuit without using any other gate. thanks in advance. Exclusive OR Gate: An exclusive OR gate (XOR gate) is a digital logic gate that is implemented using transistors in order to act as an electronic switch used in implementing Boolean functions. Because of these properties, XOR gates are commonly found in complex redstone circuits. The different logic gates are AND, OR, XOR, NOT, NAND, NOR and XNOR. Skip to main content. If we observe carefully, OUT equals B when A is '0' and B' when A is '1'. Go back to Logic Functions ↑ 6. Related faq OR gate using MUX NAND gate using MUX NOR gate using MUX XOR gate using MUX. The truth table, derived directly from the XOR truth table, uses an XOR gate with one input tied to a signal named “control”. An XOR is known as exclusive-OR gate and is almost similar to an OR gate with the only difference that when both the inputs are 1 or True, the output is 0 or False, unlike an OR gate. MOSFET Layers in an n-well process A 4-input CMOS NOR gate 2:1 multiplexer chooses between two inputs. Syntax: keyword unique_name (drain. Xor Gate Using Nor Gate. Logic Gates, NAND, XOR, NOR, OR & XNOR Logic Gates Logic gates are one of the building blocks of digital circuits, and you can use combinations of them to perform complex electronic operations. The logic gate XNOR (Exclusive NOR gate) is reverse of the XOR gate and takes two or more input and works as per the following truth table. To produce XNOR gate using OR, AND, and NOT gate, the gates are joined together as shown in figure 2. Chapter 3 Gate-Level Minimization 3-2 or NOR gates rather than with AND and OR gate! NAND and NOR gates are much easier to fabricate Generated with an XOR. These concepts are very important to grasp theme and theory of advance computer courses offered by several universities. Basically the “Exclusive-NOR” gate is a combination of the Exclusive-OR gate and the NOT gate but has a truth table similar to the standard NOR gate in that it has an output that is normally at logic level “1” and goes “LOW” to logic level “0” when ANY of its inputs are at logic level “1”. Answer: XOR(a, b) = NAND(d, e), where c = NAND(a, b), d = NAND(a, c), and e = NAND(b, c). We have seen how NAND gate can be used to make all the three basic gates by using that alone. Logic Gates, Boolean Algebra and Truth Tables. It is built by combining standard logic gates such as the common NAND and NOR gates in order to produce the more complex function of this gate. of nor gates required for implementing full adder: 9 6 5 4 asked Oct 14, 2015 in Digital Logic by gate_forum Junior ( 835 points) | 3. Basically, the XOR Gate has two input terminals and one output terminal. In this article I’m going to show you a circuit diagram of calculator using logic gates and steps to create your own calculator using logic gates. How can we prove this? (Proof for NAND gates) Any boolean function can be implemented using AND, OR and NOT gates. But basically, ANY logic can be built from a NAND gate. The outputs of all ANDed literals are then fed into one NAND gate to realize SOP (sum of product expression) as a whole. Find products. Autumn 2003 CSE370 - II - Combinational Logic 23 AB CZ 0000 0011 0100 0111 1000 1011 1101 1110 Choosing different realizations of a function two-level realization (we don’t count NOT gates) XOR gate (easier to draw but costlier to build) multi-level realization (gates with fewer inputs) Autumn 2003 CSE370 - II - Combinational Logic 24 Which. X-Gate 8-to-1 MUX 6. Modify the circuit from question 2to use a second AND gate on the chip. If any 1 of the inputs are HIGH, the output will turn on. Ask Question Asked 1 year, 9 months ago. Ultra low voltage and, nor and XOR CMOS gates Abstract: In this paper we present NAND, NOR and XOR gates exploiting the ultra low-voltage (ULV) CMOS logic style [1] [2]. Three further types of logic gate give an output that is an inverted version of the three basic gate functions listed above, and these are indicated by a bar drawn above a statement using the AND, OR, or XOR symbols to indicate NAND, NOR and XNOR. Try out the other gates by connecting them on your breadboard and see that they all behave according to the logic tables in the Boolean logic article. Each output and output of a logic gate is represented by binary conditions 0 (LOW) and 1 (HIGH). Basic Gates: Index. a b out 0 0 0 0 1 1 1 0 1 1 1 0 the xor = (a and not b) or (not a and b), which is \begin{split}\overline{A}{B}+{A}\overline{B}\end{split} I know the answer but how to get the gate diagram from the formula? EDIT. NAND gate and NOR gate are known as universal gates because we can construct all the three basic gates using NAND & NOR gates. X-Gate Logic Latch 7. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. What does xor gate mean? Information and translations of xor gate in the most comprehensive dictionary definitions resource on the web. {NAND, NOR} {XOR} {XOR, AND} X ⊕ 1 = X*1’ + X’*1 = X’ if constant “1” is available. XOR stands for 'eXclusive OR', and it's a gate that gives an output if one, but only one, of the inputs is on. How To Construct Cmos Equivalent Of An Xnor Gate Using And. There's an obvious reason this is known as a half adder. Implement NOT using NAND A A. Working of all logic gates with 8051 project. Using this XOR gate, reduction in size of full adder is achieved and overall leakage is also reduced. What is Logic XNOR or Exclusive-NOR Gate? XNOR Gate Logic Symbol, Boolean Expression & Truth Table XNOR Gate Symbol Boolean Expression Truth Table XNOR Gate Logic flow Schematic Diagram Construction and Working Mechanism of XNOR Gate XNOR Gate Using BJT and Diodes XNOR Gate Using MOSFET and Diodes XNOR Gate From other Logic Gates: (Combinational Logic) Sum of Product Using NOT, AND & OR Gate. For example, just a simple diagram with an or gate is like the follow. OR Gate ii. Transmission Gate Logic Design 3. You should be able to get inverter using the gate. So its output is complement of the output of an AND gate. Best Answer: It means, using only 2-input NOR gates, construct the following six 2-input gates: AND NAND OR NOR XOR XNOR You'll need NOT as well, but that is a one-input gate, so it doesn't count toward the six. This output is the parity bit. Tutorial 3: NAND, NOR, XOR and XNOR Gates in VHDL. Each output and output of a logic gate is represented by binary conditions 0 (LOW) and 1 (HIGH). The inverter is used to complement, or invert a digital signal. The relation between the Input(s) and the Output of a Logic Gate is expressed with a Truth-Table. What is Logic XOR or Exclusive-OR Gate? XOR Gate Logic Symbol, Boolean Expression & Truth Table XOR Gate Logic flow Schematic Diagram Construction and Working Mechanism of XOR Gate XOR Gate Using BJT and Diodes XOR Gate Using MOSFET and Diodes XOR Gate From other Logic Gates XOR Gate From Universal NAND & NOR Gates Multi-Input Exclusive OR Gate TTL and CMOS Logic XOR Gate IC’s Pinout for. That means that if both of its inputs are the same, the output will be 0 (false). Cmos And Ptl Hybrid Circuits. Here we are going to use 74LS32 IC for demonstration, this chip has 4 OR gates in it. Syntax: keyword unique_name (drain. For instance, a single NOR gate can have four inputs, computing. The NOR gate is also a universal gate. Gates and Circuits 2 Chapter Goals • Identify the basic gates and describe the behavior of each • Describe how gates are implemented using transistors • Combine basic gates into circuits • Describe the behavior of a gate or circuit using Boolean expressions, truth tables, and logic diagrams 3 Chapter Goals • Compare and contrast a. investigate the outputs of AND, NAND, OR, NOR, XOR and XNOR gates and “J-K master slave flip-flop” circuits when given different inputs using truth tables, 1 indicating a signal and 0 indicating none. The AND, OR and XOR gates all have complementary gates with inverted outputs. This is the schematic of BICMOS NOR Gate. So we can derive logical function or any Boolean or logic expression by combination of these gate. XOR Gate •XOR o ,r exclusive OR, gate – An XOR gate produces 0 if its two inputs are the same, and a 1 otherwise – Note the difference between the XOR gate and the OR gate; they differ only in one input situation – When both input signals are 1, the OR gate produces a 1 and the XOR produces a 0. As can be seen from the truth table, the output of an XOR gate is a logic ‘1’ when the inputs are unlike and a logic ‘0’ when the inputs are like. The focus will be on combina-tional logic (or non-regenerative) circuits that have the property that at any point in time, the output of the circuit is related to its current input signals by some Boolean expression (assuming that the transients through the logic gates have settled). Algebraically, if the two original NOR gate inputs are labelled B and C, and they are combined to form A. a logical operator whose output is true when either of two inputs are true but not both —called also exclusive or…. Newer chips (i. Label the outputs Y3Y2Y1Y0 and the inputs X3X2X1X0. 4T XOR gate to increase circuit density [11] [12]. XOR (exclusive OR) gate (54) Gates. NOR gates are one of the two basic logic gates (along with NAND gates) from which any other logic gates can be built. Show by various combinations of the switches that the circuit matches the AND gate truth-table. Similar concept can be applied to create all basic gates from 2:1 MUX. Useful for producing brief pulses for latches and clocks, from 1us to 1 second, for longer durations use a 555 monostable. The form calculates the bitwise exclusive or using the function gmp_xor. After power supply is turned on ,first we select the logic gate. This construction entails a propagation delay three times that of a single NOR gate and uses five gates. NOR gate has two or more input. Image info : Resolution:937x741 Size:40kB. Sometimes there is, however, a need for a gate that gives an output when either of the inputs is 1 but not when both are 1, i. So, a 2:1 mux can be used to implement 2-input XOR gate if we connect SEL to A, D0 to B and D1 to B'. Because of these properties, XOR gates are commonly found in complex redstone circuits. It is opposite of XOR GATE. Its output is "true" if the inputs are the same, and"false" if the inputs are different. Best Answer: It means, using only 2-input NOR gates, construct the following six 2-input gates: AND NAND OR NOR XOR XNOR You'll need NOT as well, but that is a one-input gate, so it doesn't count toward the six. Perform the following steps to obtain the minimum number of gates required: All the ANDed literals can be realized directly using a NAND gate each. NAND, NOR, EX-OR and EX-NOR Gate. Skip navigation Sign in. The final project uses all four of the NAND gates on the 4011 chip to create a NOR gate. The last missing ingredient is an inverter, which is simply tying both inputs together (check with a truth table). Logic gates are usually implemented as digital circuits using diodes and transistors. An XNOR gate is a XOR gate followed by an inverter, and is used in comparator circuits.
| 2019-08-20T20:09:32 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Xor Gate Using Nor Gate
It will only output power when one input is on, so it doesn't have the issue with the XNOR gate where you have to be able to supply power when both switches are off, and it will still make it so that toggling either of the switches will toggle the output of the XOR gate. A NOR gate made out of transistors. Today we are going to discuss Truth Table, Internal circuit and Symbol of XOR Gate. As I mentioned in Mechanic NOR gate I was working on extending the NOR-gate to a compact XOR-gate and I finally succeeded in making a prototype of it. The XOR gate is a digital logic gate that implements an exclusive or; that is, a true output (1) results if one, and only one, of the inputs to the gate is true (1). Introduction to XOR Gate. NOR gate is used in combination to perform the AND, OR and Inverter operations. Half Adder using only the NOR gate. All-optical XOR, NOR, and NAND gates are realized using two parallel SOA-MZIs. If only one of the inputs is 1 (or TRUE) th"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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- Engagement: Write with an academic, professional and engaging tone that captivates interest.
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# Xor Gate Using Nor Gate
It will only output power when one input is on, so it doesn't have the issue with the XNOR gate where you have to be able to supply power when both switches are off, and it will still make it so that toggling either of the switches will toggle the output of the XOR gate. A NOR gate made out of transistors. Today we are going to discuss Truth Table, Internal circuit and Symbol of XOR Gate. As I mentioned in Mechanic NOR gate I was working on extending the NOR-gate to a compact XOR-gate and I finally succeeded in making a prototype of it. The XOR gate is a digital logic gate that implements an exclusive or; that is, a true output (1) results if one, and only one, of the inputs to the gate is true (1). Introduction to XOR Gate. NOR gate is used in combination to perform the AND, OR and Inverter operations. Half Adder using only the NOR gate. All-optical XOR, NOR, and NAND gates are realized using two parallel SOA-MZIs. If only one of the inputs is 1 (or TRUE) th"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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http://astronomy.stackexchange.com/questions/1751/can-someone-explain-a-geostationary-orbit-in-a-simpler-way
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# Can someone explain a Geostationary Orbit in a simpler way?
According to Wikipedia (link), a geostationary orbit, geostationary Earth orbit or geosynchronous equatorial orbit (GEO), is a circular orbit 35,786 kilometres (22,236 mi) above the Earth's equator and following the direction of the Earth's rotation. An object in such an orbit has an orbital period equal to the Earth's rotational period (one sidereal day), and thus appears motionless, at a fixed position in the sky, to ground observers.
My question is then couldn't any orbit be a GEO? I mean, what about a satellite in an orbit that's say 70,000km, if the angular speed of the satellite was the same as the earth's rotation such that it always stayed in a fixed position when observed from the Earth, then isn't that a GEO orbit as well?
Sorry if this is a very basic or silly question.
-Sean
-
Interesting fact: A geostationary orbit is also called a "Clarke Orbit" after Arthur C. Clarke proposed using satellites in this orbit for global communications in a paper called "Extra-Terrestrial Relays — Can Rocket Stations Give Worldwide Radio Coverage?" in 1945. lakdiva.org/clarke/1945ww – Marc Feb 16 '14 at 3:02
The centrifugal force increases with the radius of the orbit for a fixed angular speed. The gravitational pull decreases with the radius of the orbit around Earth. The geostationary orbit is, where the two forces annihilate for the geosynchronous angular speed. The gravitational pull takes the role of the centripetal force to keep the satellite on the circular orbit.
That's the principle, which keeps satellites, moons, planets on their respective orbit. If there is some additional force, they leave their former orbit.
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The speed of a satellite in orbit is directly linked to the radius of that orbit:
$V=\frac{2*\pi*a}{T}$
V is the orbital speed, a is the radius and T is the orbital period. This means that for any radius, there is only one possible orbital speed and vice versa. So there is only one radius where the period is 24 hours.
If you really want a satellite to orbit at 70,000 km and still be geostationary, you'll have to use thrusters constantly to provide an extra force towards the Earth. This uses far too much fuel to be economical.
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@Hobbes put the formula:
$V={2\pi a\over T}$
If you substitute on it $T$ for 1 sidereal day you'll have a one-to-one relation between $V$ and $a$. This seems to imply that you can choose any $a$ and use the corresponding $V$, but this is not true since it does not take into account which force are you using.
The formula above is valid of any object in a circular motion, like a stone on a sling, or a car in a loop. It is also valid for satellites around planets.
But there is another formula stating a relation among $a$ and $T$ when the force is that of Gravity, so you are not free to chose $a$ anymore.
It happens that centripetal acceleration (that of the sling, the Normal force on the loop, or gravity for the satellite) is the Universal Gravity in our case:
$a_c={GM\over r^2}$
but it being the centripetal acceleration means
$a_c=\omega^2 r$
so we have
$\omega^2 r={GM\over r^2}$
$\omega^2 r^3=GM$
$\omega$ is $v\over r$ so
$v^2 r=GM$
which gives you a fixed relation between $v$ and $r$ for any planet with mass $M$.
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I like your answer, but decide to upvote another because the question asked for a simple explanation. – astabada Feb 19 '14 at 8:59
You have yourself provided us with the answer.
Any satellite revolving over the Earth's Equator would be considered as a GeoStationary object. Provided, it should move with the rotation of the Earth and it should be 35,786 kilometres above of the sea so that the observer, that is on the ground would think that the satellite is stationary.
If to say for simple:
A Geostationary object is an object, which is fully synchronized to the movement of the earth. Its position is as it is fixed to the Equator of the earth at zero degree latitude.
Anything that would stay synchronized with the Earth's rotation would be a Geostationary object.
Apart from the Wikipedia article you can read more here: http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Geostationary_orbit.html
It has clear and more simple information, and has described that the object must be this_many kms above the sea level and should be at the 0 degree latitude.
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Not correct. Geostationary objects do not have the exact same orbit. They are not on exactly circular orbits, they are not all at the exact same altitude, and they are not all on the Equator plane. Besides, you did not answer the base question. – Envite Feb 17 '14 at 10:27
If an orbit is not on the equatorial plane, it's not geostationary. It may be geosynchronous, though. Similarly, if an orbit isn't circular, the satellite's apparent position in the sky will vary as the angular speed increases, then decreases. It might be close enough for operational purposes, but it's not exactly geostationary. – Hobbes Jun 25 '15 at 15:53
In a simpler way, if that satellite is above 35,786 kilometres above you country place, for example, Inidia-Dehli, then satellite will remain at the same position throughout its life. That is why it is called as Geostationary satellite. It revolves with the speed of earth, but circumference of earth and circumference of geostationary satellite's orbit is different. Circumference of geostationary satellite is much greater than the earths circumference. So speed of geostationary satellite is greater than speed of earth because it has to stick to you country place above earth so it have to move fast.
Also in this orbit, gravitational force of earth which attracts satellite towards earth and centrifugal force which tries to escape satellite from that orbit (due to the velocity of satellite), works in synchronous way, and it becomes neutral. So that satellite keeps revolving around at fixed position. So, such orbit is known as Geostationary orbit.
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| 2016-02-11T04:29:06 |
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"url": "http://astronomy.stackexchange.com/questions/1751/can-someone-explain-a-geostationary-orbit-in-a-simpler-way",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Can someone explain a Geostationary Orbit in a simpler way?
According to Wikipedia (link), a geostationary orbit, geostationary Earth orbit or geosynchronous equatorial orbit (GEO), is a circular orbit 35,786 kilometres (22,236 mi) above the Earth's equator and following the direction of the Earth's rotation. An object in such an orbit has an orbital period equal to the Earth's rotational period (one sidereal day), and thus appears motionless, at a fixed position in the sky, to ground observers.
My question is then couldn't any orbit be a GEO? I mean, what about a satellite in an orbit that's say 70,000km, if the angular speed of the satellite was the same as the earth's rotation such that it always stayed in a fixed position when observed from the Earth, then isn't that a GEO orbit as well?
Sorry if this is a very basic or silly question.
-Sean
-
Interesting fact: A geostationary orbit is also called a "Clarke Orbit" after Arthur C. Clarke proposed using satellites in this orbi"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Can someone explain a Geostationary Orbit in a simpler way?
According to Wikipedia (link), a geostationary orbit, geostationary Earth orbit or geosynchronous equatorial orbit (GEO), is a circular orbit 35,786 kilometres (22,236 mi) above the Earth's equator and following the direction of the Earth's rotation. An object in such an orbit has an orbital period equal to the Earth's rotational period (one sidereal day), and thus appears motionless, at a fixed position in the sky, to ground observers.
My question is then couldn't any orbit be a GEO? I mean, what about a satellite in an orbit that's say 70,000km, if the angular speed of the satellite was the same as the earth's rotation such that it always stayed in a fixed position when observed from the Earth, then isn't that a GEO orbit as well?
Sorry if this is a very basic or silly question.
-Sean
-
Interesting fact: A geostationary orbit is also called a "Clarke Orbit" after Arthur C. Clarke proposed using satellites in this orbi"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://tex.stackexchange.com/questions/115521/set-bullet-instead-of-dot-using-dot
|
# Set bullet instead of dot using \dot
I would like to place a bullet in the same way that $\dot{x}$ places a dot above x. Does anyone have a clue?
Another clear case for the accents package: .
\documentclass{article}
\usepackage{accents}
\begin{document}
$\accentset{\bullet}{x}$
\end{document}
Note that, in contrast to \overset, the slant of the letters is taken care of automatically:
Here you go:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$A \overset{\bullet}{B} C$
\end{document}
• It would be worth editing your question to clarify, then, as that's the first thing everyone will see when they click this thread. – ach May 22 '13 at 10:52
I used the \; to add some horizontal space before the bullet, to account for the fact that the under-letter will be set in italic which is generally slanted:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\overset{\;\bullet} B$
\end{document}
| 2020-07-10T17:08:34 |
{
"domain": "stackexchange.com",
"url": "https://tex.stackexchange.com/questions/115521/set-bullet-instead-of-dot-using-dot",
"openwebmath_score": 0.7807937264442444,
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"lm_q1q2_score": 0.5000161808963631
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Set bullet instead of dot using \dot
I would like to place a bullet in the same way that $\dot{x}$ places a dot above x. Does anyone have a clue?
Another clear case for the accents package: .
\documentclass{article}
\usepackage{accents}
\begin{document}
$\accentset{\bullet}{x}$
\end{document}
Note that, in contrast to \overset, the slant of the letters is taken care of automatically:
Here you go:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$A \overset{\bullet}{B} C$
\end{document}
• It would be worth editing your question to clarify, then, as that's the first thing everyone will see when they click this thread. – ach May 22 '13 at 10:52
I used the \; to add some horizontal space before the bullet, to account for the fact that the under-letter will be set in italic which is generally slanted:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\overset{\;\bullet} B$
\end{document}"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Set bullet instead of dot using \dot
I would like to place a bullet in the same way that $\dot{x}$ places a dot above x. Does anyone have a clue?
Another clear case for the accents package: .
\documentclass{article}
\usepackage{accents}
\begin{document}
$\accentset{\bullet}{x}$
\end{document}
Note that, in contrast to \overset, the slant of the letters is taken care of automatically:
Here you go:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$A \overset{\bullet}{B} C$
\end{document}
• It would be worth editing your question to clarify, then, as that's the first thing everyone will see when they click this thread. – ach May 22 '13 at 10:52
I used the \; to add some horizontal space before the bullet, to account for the fact that the under-letter will be set in italic which is generally slanted:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\overset{\;\bullet} B$
\end{document}"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://electronics.stackexchange.com/questions/435856/how-to-determine-the-best-resistance-for-a-weak-signal-twin-t-notch-filter
|
# How to determine the best resistance for a weak signal Twin-T notch filter?
I am designing a 50/60 Hz Twin-T notch filter for a weak (biomedical) signal output from an instrument amplifier (InAmp) to be chained to another active low pass filter. The input frequency range is between 0.1 Hz to ~200 Hz.
Image credit: here
I have come across several designs, using widely different values for $$\R\$$, often ranging from $$\100\ k\Omega\$$ to $$\10\ M\Omega\$$.
I'm getting a quite confused about how these values are best chosen.
On the one hand:
1. It has been stated that perhaps the circuit would draw less current, but I don't see this, as there is no obvious current sink between the input and the output.
2. That there is some kind of impedance matching going on. Impedance of what? (The InAmp output or the OA input?)
3. It may be easier to find matching capacitors when using a larger R, for a given $$\f_c = 1/(2 \pi R C) = 50\ Hz \$$
On the other hand:
1. There may be significant thermal noise, for higher R as given by:
$$\V_{n(rms)} = \sqrt{4k_BT R\Delta f} \approx 1.623\ \mu V\$$ (for R=2.6M, C=1n)
thus approaching that of the signal itself, $$\ <100 \mu V\$$.
2. Similarly, using larger R, implies using a smaller C, subsequently increasing the capacitor thermal noise too.
3. Then I suppose there are all sorts of other noise types (such as 1/f) to consider, but whose relevance to R is not clear.
As you can see, my mind is already clipping long before my signals do.
How can I sort this out to better understand what values for R (or C) to use?
UPDATE
So far it seem that the best choice is trying to keep R as small as possible within reason, probably within 100 kΩ ≤ R < 1 MΩ. This will have the following consequences:
• Reduce the thermal noise
• Increase the value needed for C, also reducing noise
• Noise $$\V_n \propto\ \sqrt{I}\$$ which implies that SNR improves as well.
What else:
• C values are the most limiting, since they are only readily available in the E12 value series, whereas R is in E96 (and even E192.)
• C should be > 1 nF due to possible PCB stray capacitance.
• C should be of polyester or Mylar type.
• R should be of type metal film @ 1% for lowest noise.
• I/O impedance is irrelevant, because of the previous and subsequent use of InAmp & OpAmp.
• What about RF filtering? (4/5G mobile phone nearby?)
• Ooops. Didn't realize you were still working on it. – JRE Apr 28 '19 at 11:20
1) The circuit itself won't "draw less current" from the supply, but it will draw less (or more) from the In-Amp; which will ultimately get that from its supply. There IS an obvious current sink : the low output impedance of the feedback buffer. This amplifier, too, is powered from the supply. However, why are you concerned about the supply current? What are your constraints here?
For noise analysis, treat that current sink - buffer output - as ground, or more accurately, as a noise voltage source (determined by the amplifier, and its source impedance) in series with ground.
2) Between an in-amp (low Z output) and opamp input (high Z input) there isn't any impedance matching to worry about. If you are responsible for the in-amp stage, it's worth knowing the source impedance of the sensor, to design a front end (InAmp) with appropriate noise impedance, but given the question, that's a SEP (Somebody Else's Problem).
3) High values of close tolerance caps (usually metal foil or metal film caps) can be expensive but I'll assume your budget runs to 10 uF or so (which also tend to be physically large) giving a lower bound on your resistance at 318 ohms.
4) Yes; thermal noise may be a major problem. Reducing R helps (adding cost to C, see 3) but don't go overboard. If the noise in this stage is 10dB lower than the source noise * front end gain, it will only add 1 dB to the overall noise figure. You know that context; we don't; but there isn't much point going below that 1dB noise figure.
5) A capacitor isn't a thermal noise source. A resistor works via collisions between electrons and the atoms within the resistance; the statistics of those collisions are the noise source. There is no similar noise mechanism in a capacitor.
However, whenever a current divides between two alternative paths, each electron takes one path or the other, the statistics of this giving partition noise. Noise is proportional to sqrt(current) so signal/noise also improves as sqrt(current) (assuming the current is all signal, no DC bias)
6) While some resistors may be 1/F noise sources (carbon composition?) you can use metal film instead. The amplifiers (in-amp and buffers) are 1/F noise sources. Compare their specs with your requirements. (Note that at these low bandwidths, there are chopper stabilised amplifiers that move the "1/F" noise out to their chop frequency, which may be 200kHz and well outside your band of interest)
TL/DR : Reduce R as far as (a) system performance needs - see front end noise, 4) and (b) current and cost budgets (1,3) permit.
• Regarding (5). According to wikipedia there is thermal noise also on caps. – not2qubit Apr 28 '19 at 15:04
• but "The noise is not caused by the capacitor itself", it is the development of the resistor's noise across the capacitor. They are quite right, the R terms cancel out in the expression. But keeping R-C constant, you get the same relative answer : reducing R and increasing C both reduce noise. – Brian Drummond Apr 28 '19 at 15:16
| 2020-01-17T21:22:47 |
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"domain": "stackexchange.com",
"url": "https://electronics.stackexchange.com/questions/435856/how-to-determine-the-best-resistance-for-a-weak-signal-twin-t-notch-filter",
"openwebmath_score": 0.698805034160614,
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"lm_name": "Qwen/Qwen-72B",
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"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# How to determine the best resistance for a weak signal Twin-T notch filter?
I am designing a 50/60 Hz Twin-T notch filter for a weak (biomedical) signal output from an instrument amplifier (InAmp) to be chained to another active low pass filter. The input frequency range is between 0.1 Hz to ~200 Hz.
Image credit: here
I have come across several designs, using widely different values for $$\R\$$, often ranging from $$\100\ k\Omega\$$ to $$\10\ M\Omega\$$.
I'm getting a quite confused about how these values are best chosen.
On the one hand:
1. It has been stated that perhaps the circuit would draw less current, but I don't see this, as there is no obvious current sink between the input and the output.
2. That there is some kind of impedance matching going on. Impedance of what? (The InAmp output or the OA input?)
3. It may be easier to find matching capacitors when using a larger R, for a given $$\f_c = 1/(2 \pi R C) = 50\ Hz \$$
On the other hand:
1. There may be significan"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# How to determine the best resistance for a weak signal Twin-T notch filter?
I am designing a 50/60 Hz Twin-T notch filter for a weak (biomedical) signal output from an instrument amplifier (InAmp) to be chained to another active low pass filter. The input frequency range is between 0.1 Hz to ~200 Hz.
Image credit: here
I have come across several designs, using widely different values for $$\R\$$, often ranging from $$\100\ k\Omega\$$ to $$\10\ M\Omega\$$.
I'm getting a quite confused about how these values are best chosen.
On the one hand:
1. It has been stated that perhaps the circuit would draw less current, but I don't see this, as there is no obvious current sink between the input and the output.
2. That there is some kind of impedance matching going on. Impedance of what? (The InAmp output or the OA input?)
3. It may be easier to find matching capacitors when using a larger R, for a given $$\f_c = 1/(2 \pi R C) = 50\ Hz \$$
On the other hand:
1. There may be significan"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://chemistry.stackexchange.com/questions/112835/cp-vs-cv-for-liquid-water-4-c
|
Cp vs Cv for liquid water @ < 4 °C
I'm looking at a textbook question (Engel & Reid, Thermodynamics, Statistical Thermodynamics & Kinetics, 4 ed, Q3.1) which states the following:
The heat capacity $$C_{\mathrm m,p}$$ is less than $$C_{\mathrm m,V}$$ for $$\ce{H2O(l)}$$ near $$\pu{4 °C}$$. Explain this result.
Their answer is that water contracts as you heat it in this regime, thus (at constant $$p$$) the surroundings are doing work on the system, hence $$C_{\mathrm m,p}\lt C_{\mathrm m,V}$$.
But the textbook also contains the following equation (which is correct, and whose only restrictions are that the system is of fixed phase and composition, and $$\text{đ}w = –pdV$$, i.e., pV-work only):
$$C_{\mathrm m,p}-C_{\mathrm m,V} = T V_\mathrm m \beta^2/\kappa$$
where $$\beta$$ is the isobaric thermal expansivity, and $$\kappa$$ is the isothermal compressibility.
Based on this, for a substance of fixed phase and composition, $$C_{\mathrm m,p} \ge C_{\mathrm m,V}$$, always, because, while $$\beta$$ can be $$\le0$$* (water near $$\pu{4 °C}$$ being a notable example), $$\beta^2$$, as well as $$T, V_\mathrm m$$ and $$\kappa$$, are always positive. [*Edited from $$\lt 0$$ to $$\le 0$$ based on Night Writer's answer.]
So is the statement in the textbook's question just a flat-out mistake, or am I missing something here?
It appears their error is in assuming the difference between Cp and Cv is due to pV expansion alone, when in fact there are two terms:
$$C_p - C_V = p \left(\partial V\over\partial T\right)_p+ \left(\partial U\over\partial V\right)_T \left(\partial V\over\partial T\right)_p,$$
where the first term on the RHS is the PV work per unit change in T, while the second term is the change in internal energy with respect to volume (which results from changing the intermolecular distance between interacting particles) times the rate at which the volume changes with temperature.
It would be nice to have direct reference-quality experimental values for $$C_{\mathrm m,p}$$ and $$C_{\mathrm m,V}$$ for $$\ce{H2O(l)}$$ near $$\pu{4 °C}$$, but I've not been able to locate them, nor do I expect to: because of the difficulty of accurately measuring $$C_{\mathrm m,V}$$ for a liquid, measurements are typically made at constant pressure, giving $$C_{\mathrm m,p}$$, and then $$C_{\mathrm m,V}$$ is calculated using the above equation.
• In addition to the answers below, the data do show that $C_p \gt C_V$, albeit by a very small amount near zero $^\circ$C ($\approx 0.05$ J/mol/K) at temperatures from just above zero to 10 $^\circ$C. So the question is factually wrong. Apr 16, 2019 at 10:38
• @porphyrin Can you provide a reference for that data? Apr 16, 2019 at 15:04
• I just looked on the web: engineeringtoolbox.com/specific-heat-capacity-water-d_660.html . Apr 16, 2019 at 19:53
• @porphyrin I suspect the only experimental data there is for Cp, and that Cv was calculated from the Cp values using the above formula. There's no way to tell without a reference to the original source. Apr 16, 2019 at 20:13
• Ok, I had'n't realised that. You will have to search for some original data, but I can see no reason why $C_v$ should be greater than $C_p$. That $\beta \to 0$ seems to be the best explanation as shown by @ Night Writer in that answer. Apr 17, 2019 at 6:27
Repeating your line of reasoning, if $$C_{\mathrm m,p} you would conclude based on the expression you provide ($$C_{\mathrm m,p}-C_{\mathrm m,V} = T V_\mathrm m \alpha^2/\kappa$$) that $$\kappa<0$$ which in turn would mean that
$$\left(\frac{\partial V_m}{\partial P}\right)_T > 0,\label{eqn:1}\tag{1}$$
which is not physically reasonable except presumably in some very unusual circumstances. Therefore, either the question statement contains a fallacy, or the above analysis contains a fallacy, i.e. $$\eqref{eqn:1}$$ is reasonable. My bet is on the first scenario, as you suggest.
What seems to happen is that near $$\pu{4 °C}$$
$$C_{\mathrm m,p} = C_{\mathrm m,V}\label{eqn:2}\tag{2}$$
because the change in the density or molar volume with $$T$$ (and therefore also the thermal expansion coefficient $$\beta$$ - usually designated with the symbol $$\alpha$$) becomes zero, that is there is a (well known) minimum in the dependence of the density or molar volume on $$T$$ at constant $$P$$, illustrated in the following figure (source: wikipedia)
In agreement with this, if you inspect available heat capacity data you will see that the isochoric and isobaric heat capacities converge as the temperature of liquid water nears $$\pu{0 °C}$$.
The International Association for the Properties of Water and Steam has released a document (IAPWS R7-97(2012)) containing expressions for the heat capacities of water parameterized based on experimental data (see Table 3).
• That's a nice point about $\beta$ for water going to zero at 4C. Apr 16, 2019 at 20:23
• @theorist I think the answer is a combination of my explanation and the alternate answer: that answer explains some of the flaws in the book's reasoning, mine explains others (well, I echo your explanation - good catch - and follow it to it's logical conclusion based on the available data). I did find some standard data but have not crunched the numbers. Apr 20, 2019 at 19:43
The textbook's question is flawed because, as you state, its assertion that $$c_p < c_v$$ is false.
The textbook's answer messes up the math a little bit. Their logic is based on the First Law:
\begin{align} \Delta u &= q - P \Delta v \\ q &= \Delta u + P \Delta v \end{align} Considering an isobaric process, we have \begin{align} \overbrace{c_p \Delta T}^q &= \overbrace{\left(\frac{\partial u}{\partial T}\right)_P \Delta T}^{\Delta u} + P \overbrace{\left(\frac{\partial v}{\partial T}\right)_P \Delta T}^{\Delta v} \\ c_p &= \underbrace{\left(\frac{\partial u}{\partial T}\right)_P}_X + \underbrace{\left(\frac{\partial v}{\partial T}\right)_P}_{<0} \end{align} If term $$X$$ were the same as $$c_v$$ then it would follow that $$c_p < c_v$$, but the wrong property is held constant: $$c_v$$ would be $$\left(\frac{\partial u}{\partial T}\right)_v$$. Evidently $$\left(\frac{\partial u}{\partial T}\right)_P - \left(\frac{\partial u}{\partial T}\right)_v$$ is more positive than $$P \left(\frac{\partial v}{\partial T}\right)_P$$ is negative. The textbook seems to be incorrectly assuming that $$X = c_v$$.
Note that the corner case $$c_p = c_v$$ is allowed; this would occur when $$\beta = 0$$, $$T = 0$$, $$v = 0$$, or $$\kappa = \infty$$ (the first case being the one that can actually occur in everyday life).
Original take-down of the textbook answer:
Based on your summary, the textbook's answer fails to account for the fact that switching from an isobaric path to an isothermal path changes the end state. The (flawed) logic seems to be: "if I go from A to B isochorically then I need to provide some amount of heat, but if I go from A to B isobarically then the surroundings provide some work so I don't need to provide as much heat." The flaw is that if A-B is an isochor then an isobar beginning at A doesn't go through B. An apples-to-oranges comparison would consider the heat required to reach a third point C which is at the same pressure as A and temperature as B, and would find that this heat is never lower than that required to reach B.
• You seem to be saying the textbook's answer is flawed because you can't compare Cp and Cv, the reason being that the difference in constraints implicit to Cp vs. Cv brings you to different final states (making it apples to oranges). However, even with this, you certainly can compare Cp to Cv (their difference is $TV\beta^2/\kappa$). Thus (and forgive me if I'm not understanding you correctly) I don't think the specific issue you raise (the difference in final states) is relevant here. I.e., I think the textbook is wrong, but not for the reason you give. Apr 16, 2019 at 22:05
• I'm saying that their argument that the isobaric process involves less work than the isochoric process is overly simplistic (because it assumes the two processes have the same endpoint). You can certainly compare $c_p$ and $c_v$, for example using the formula you provided, but their attempt to provide an explanation based directly on the First Law/intuition is flawed. Apr 16, 2019 at 22:52
• I think their argument is flawed, but not for the reason you give. The problem isn't that they don't go to the same endpoint; that doesn't preclude the comparison. For instance, it's not a problem to say the reason Cp = Cv +nR for an ideal gas is that, during constant-P heating, you have to input additional thermal energy for the PV work associated with expansion. By your argument, you couldn't make a universal statement like that for ideal gases simply because they don't go to the same final state in a constant-V vs a constant-P heating. But that's simply not the case. [continued....] Apr 17, 2019 at 0:55
• ...Hence the disparity of final states is not the logical issue per se. Rather, I think the reason their argument is simplistic/flawed is that it doesn't account for the difference in internal energy due to changes in volume in real materials (which have attractive and repulsive interactions). I.e., it accounts only for the difference in the work done on the surroundings. I.e., you're saying that the problem is that they're comparing processes with different final states. I'm saying it's OK for the final states to be different, so long as you account for the effect of those differences. Apr 17, 2019 at 0:57
• I suppose we are arguing over what is the "right" way is to do something wrong, haha. You have the advantage of actually having read the textbook's answer in its entirety ;) I have updated my answer to reflect the flaw that you see but also retained the flaw that I saw so that our comment chain still makes sense. Apr 17, 2019 at 1:50
| 2022-05-24T00:41:41 |
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"url": "https://chemistry.stackexchange.com/questions/112835/cp-vs-cv-for-liquid-water-4-c",
"openwebmath_score": 0.6971212029457092,
"openwebmath_perplexity": 577.1806324374991,
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"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
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|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Cp vs Cv for liquid water @ < 4 °C
I'm looking at a textbook question (Engel & Reid, Thermodynamics, Statistical Thermodynamics & Kinetics, 4 ed, Q3.1) which states the following:
The heat capacity $$C_{\mathrm m,p}$$ is less than $$C_{\mathrm m,V}$$ for $$\ce{H2O(l)}$$ near $$\pu{4 °C}$$. Explain this result.
Their answer is that water contracts as you heat it in this regime, thus (at constant $$p$$) the surroundings are doing work on the system, hence $$C_{\mathrm m,p}\lt C_{\mathrm m,V}$$.
But the textbook also contains the following equation (which is correct, and whose only restrictions are that the system is of fixed phase and composition, and $$\text{đ}w = –pdV$$, i.e., pV-work only):
$$C_{\mathrm m,p}-C_{\mathrm m,V} = T V_\mathrm m \beta^2/\kappa$$
where $$\beta$$ is the isobaric thermal expansivity, and $$\kappa$$ is the isothermal compressibility.
Based on this, for a substance of fixed phase and composition, $$C_{\mathrm m,p} \ge C_{\mathrm m,V}$$, always, because, w"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Cp vs Cv for liquid water @ < 4 °C
I'm looking at a textbook question (Engel & Reid, Thermodynamics, Statistical Thermodynamics & Kinetics, 4 ed, Q3.1) which states the following:
The heat capacity $$C_{\mathrm m,p}$$ is less than $$C_{\mathrm m,V}$$ for $$\ce{H2O(l)}$$ near $$\pu{4 °C}$$. Explain this result.
Their answer is that water contracts as you heat it in this regime, thus (at constant $$p$$) the surroundings are doing work on the system, hence $$C_{\mathrm m,p}\lt C_{\mathrm m,V}$$.
But the textbook also contains the following equation (which is correct, and whose only restrictions are that the system is of fixed phase and composition, and $$\text{đ}w = –pdV$$, i.e., pV-work only):
$$C_{\mathrm m,p}-C_{\mathrm m,V} = T V_\mathrm m \beta^2/\kappa$$
where $$\beta$$ is the isobaric thermal expansivity, and $$\kappa$$ is the isothermal compressibility.
Based on this, for a substance of fixed phase and composition, $$C_{\mathrm m,p} \ge C_{\mathrm m,V}$$, always, because, w"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://stats.stackexchange.com/questions/301675/selecting-k-with-elbow-method-for-k-modes-binary-or-nominal-data
|
# Selecting K with elbow method for K-modes (binary or nominal data)
I have run the k-modes algorithm on my nominal data set, which I converted to a dummy matrix (binary). As for K-Means, one can perform the elbow method by looking at the elbow method using, according to Wikipedia, the Percentage of variance explained is the ratio of the between-group variance to the total variance, also known as an F-test source.
How would one compute the between-group variance ratio or simply the SS(W) for a nominal/binary data set? Are there available approaches?
Thanks for any help and insights!
PS: I have already performed the silhouette score using jaccard index or dice from the using scipy library and would like to compute the elbow method as well.
• Variance is for continuous variables, not nominal data. – Has QUIT--Anony-Mousse Sep 10 '17 at 8:40
• @Anony-Mousse Hence my question. Is there a comparable approach for nominal data? I have encountered Unalikeability (Kader et al 2007; ww2.amstat.org/publications/jse/v15n2/kader.pdf) but I am unsure if one could employ it in a similar fashion – dmeu Sep 11 '17 at 14:04
• Well, many distance-based methods like Silhouette can still be used if you have a distance function. But that doesn't mean they will be very reliable, but mostly can serve as a first guess. Some of these will require you finding an "elbow" too... – Has QUIT--Anony-Mousse Sep 11 '17 at 18:47
• Refer to the below link might be of some help. kaggle.com/ashydv/bank-customer-clustering-k-modes-clustering/… – Rick.code Jun 17 at 18:05
| 2020-09-27T05:00:02 |
{
"domain": "stackexchange.com",
"url": "https://stats.stackexchange.com/questions/301675/selecting-k-with-elbow-method-for-k-modes-binary-or-nominal-data",
"openwebmath_score": 0.5200368762016296,
"openwebmath_perplexity": 1230.2793121984755,
"lm_name": "Qwen/Qwen-72B",
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"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Selecting K with elbow method for K-modes (binary or nominal data)
I have run the k-modes algorithm on my nominal data set, which I converted to a dummy matrix (binary). As for K-Means, one can perform the elbow method by looking at the elbow method using, according to Wikipedia, the Percentage of variance explained is the ratio of the between-group variance to the total variance, also known as an F-test source.
How would one compute the between-group variance ratio or simply the SS(W) for a nominal/binary data set? Are there available approaches?
Thanks for any help and insights!
PS: I have already performed the silhouette score using jaccard index or dice from the using scipy library and would like to compute the elbow method as well.
• Variance is for continuous variables, not nominal data. – Has QUIT--Anony-Mousse Sep 10 '17 at 8:40
• @Anony-Mousse Hence my question. Is there a comparable approach for nominal data? I have encountered Unalikeability (Kader et al 2007; ww2.ams"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Here's an extract from a webpage:
"# Selecting K with elbow method for K-modes (binary or nominal data)
I have run the k-modes algorithm on my nominal data set, which I converted to a dummy matrix (binary). As for K-Means, one can perform the elbow method by looking at the elbow method using, according to Wikipedia, the Percentage of variance explained is the ratio of the between-group variance to the total variance, also known as an F-test source.
How would one compute the between-group variance ratio or simply the SS(W) for a nominal/binary data set? Are there available approaches?
Thanks for any help and insights!
PS: I have already performed the silhouette score using jaccard index or dice from the using scipy library and would like to compute the elbow method as well.
• Variance is for continuous variables, not nominal data. – Has QUIT--Anony-Mousse Sep 10 '17 at 8:40
• @Anony-Mousse Hence my question. Is there a comparable approach for nominal data? I have encountered Unalikeability (Kader et al 2007; ww2.ams"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://cs.stackexchange.com/questions/44583/inducing-a-context-free-grammar?noredirect=1
|
# Inducing a context free grammar [closed]
I have a file containing a subset of possible strings from a context free language. I am looking for a mechanism to induce the grammar from this information. Is that possible?
• One grammar just lists each string as a production for the start symbol. There are clearly an infinite number of grammars that generate the given strings, so without any other criteria on the grammar, this problem just has no possible answer. Jul 23, 2015 at 2:34
• This question falls a bit short (cf vonbrand) but it's also way too broad; learning grammars in an entire research subfield!
– Raphael
Jul 24, 2015 at 6:15
• It wasn't obvious to me that having only positive examples is not enough to induce a grammar. The answer by @D.W. made that clear. While I understand that grammar induction itself is a sizable field of research, wouldn't this question and the accepted answer below help someone else like me overcome the same misconception? Jul 25, 2015 at 15:44
If you have only positive examples (strings that are in the language), in principle, no, you cannot infer the grammar. For all you can tell, the language might be $\Sigma^*$: no matter how many example strings you have, you'll never be able to rule that out as the language.
| 2022-09-25T10:59:09 |
{
"domain": "stackexchange.com",
"url": "https://cs.stackexchange.com/questions/44583/inducing-a-context-free-grammar?noredirect=1",
"openwebmath_score": 0.4518177807331085,
"openwebmath_perplexity": 559.5518245629028,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Inducing a context free grammar [closed]
I have a file containing a subset of possible strings from a context free language. I am looking for a mechanism to induce the grammar from this information. Is that possible?
• One grammar just lists each string as a production for the start symbol. There are clearly an infinite number of grammars that generate the given strings, so without any other criteria on the grammar, this problem just has no possible answer. Jul 23, 2015 at 2:34
• This question falls a bit short (cf vonbrand) but it's also way too broad; learning grammars in an entire research subfield!
– Raphael
Jul 24, 2015 at 6:15
• It wasn't obvious to me that having only positive examples is not enough to induce a grammar. The answer by @D.W. made that clear. While I understand that grammar induction itself is a sizable field of research, wouldn't this question and the accepted answer below help someone else like me overcome the same misconception? Jul 25, 2015 at 15:44
If you"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Inducing a context free grammar [closed]
I have a file containing a subset of possible strings from a context free language. I am looking for a mechanism to induce the grammar from this information. Is that possible?
• One grammar just lists each string as a production for the start symbol. There are clearly an infinite number of grammars that generate the given strings, so without any other criteria on the grammar, this problem just has no possible answer. Jul 23, 2015 at 2:34
• This question falls a bit short (cf vonbrand) but it's also way too broad; learning grammars in an entire research subfield!
– Raphael
Jul 24, 2015 at 6:15
• It wasn't obvious to me that having only positive examples is not enough to induce a grammar. The answer by @D.W. made that clear. While I understand that grammar induction itself is a sizable field of research, wouldn't this question and the accepted answer below help someone else like me overcome the same misconception? Jul 25, 2015 at 15:44
If you"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://crypto.stackexchange.com/tags/reference-request/hot
|
Tag Info
Digital signature that is only verifiable by one specific person
What you seem to be looking for is deniable authentication. This is actually a somewhat stronger property than what you're asking for: it guarantees that the recipient (let's call him Bob) cannot ...
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Examples of modern, widely used ciphers that suddenly fell?
This question is quite broad by specifying a sudden fall to cryptanalysis and therefore my answer might not be as complete as you wish it to be. If by "become practically attackable, or close enough ...
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Is secp256r1 more secure than secp256k1?
The curves secp256r1 and secp256k1 have comparable security. If we consider only the best known attacks today, they have very close security. Both curves are defined over prime fields and have no ...
• 6,744
Accepted
What was NIST’s reason to switch naming from MD… (Message Digest) to SHA… (Secure Hashing Algorithm)?
When NIST introduced SHA-0 in 1993, they – for the first time – switched their naming convention from MD-n to SHA-n Actually, MD-n was not NIST's naming conventions; it was RSA Security's (a private ...
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Does AES-NI offer better side-channel protection compared to AES in software?
Yes, AES-NI was specifically designed to be constant-time and thus offers better side-channel protection than (some) software implementations. Note however that these day there exist quite fast side-...
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Developing algorithm for detecting plain text via frequency analysis
As otus suggests in the comments, it's better to first calculate the frequency of each letter in the decrypted message, and then compare the frequency distribution to what would be expected for ...
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Use case for extendable-output functions (XOF) such as SHAKE128/SHAKE256
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• 45.3k
Difference between “ECDH with cofactor key” and “ECDH without cofactor key”?
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This is true of any group of prime order, over elliptic curves or not. This is due to Lagrange's Theorem which states that the order of a subgroup $H$ of group $G$ divides the order of $G$. Since ...
• 721
Does AES-NI offer better side-channel protection compared to AES in software?
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Is Bruce Schneier Applied Cryptography, Second ed. up to date?
The Applied Cryptography Second Edition goes back to 1996. Although there is a 20th-anniversary edition, 2015, it is not updated as one thought. If you look for Schneier's style, you may look at the ...
• 45.7k
Status of Algebraic Eraser key exchange?
The first part of this partial self-answer uses additional information I received from Professor Simon R. Blackburn, one of the author of the recent attack. The method used to generate parameters is ...
• 132k
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Why cannot I assume that cryptography published in venues/journals handled by the same publishers as prestigious journals is serious?
In addition to the (good) response of kodlu, let me clarify a point which, I think, is the source of the confusion. Springer, IEEE, Elsevier, etc, are publishers. What this means is that they are ...
• 18.3k
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Is there an encryption format that preserves length and only outputs alphanumerics?
Both of the other answers tackle the question of encryption in a particular format, but I would argue that neither of them is necessarily a good fit for your use case. You want to be able to generate ...
• 31.8k
Digital signature that is only verifiable by one specific person
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Where can I find a description of the SHA-0 hash algorithm?
The reference on SHA(-0) is FIPS 180 (archived scan) of 1993 May 11. The standard itself is referenced on the NIST website, but that links to another scan lacking page 1 and the one before, thus ...
• 132k
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What choice did they have? F1 is a bitwise function with three inputs and one output. There are $2^8 = 256$ such functions. Only 70 of them are "unbiased" (i.e. have as many 0 and 1 outputs in their ...
• 31.8k
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Who is the inventor of the OFB block cipher mode of operation?
It's difficult to be sure of the attribution here, but my best guess would be Carl M. Campbell Jr., from the (later renamed to Mastercard) Interbank Card Association. Soon after the DES was ...
• 12.1k
Is there a string that's hash is equal to itself?
Yes, you can create many such functions. For instance, lets build such a function based on SHA512. Generate some random value $m_0$ and generate a hash of it. It is important, because there is no ...
• 2,513
Accepted
Here is a blog where Scott Aaronson wrote about this, including a link to the NSA document. That link is however now broken, but the blog contains all of the needed text. An alternative copy of the ...
• 27.3k
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Clarification of the provable cryptography controversies
In general, that article seems to be referring to the "Another Look At..." line of work. Many of the papers are collated on this website. There are a number of "controversies" you ...
• 10.5k
Accepted
Which cryptography technique does not increase the size of the plain data?
The standard answer to this question is format-preserving encryption (FPE). FPE is a class of techniques that allow you to encrypt data while preserving some of its format (which can include its ...
• 4,606
Accepted
Efficiency of oblivious algorithms vs non-oblivious algorithms?
Yes. There is an $\Omega(\log n)$ lower bound on ORAM. Therefore directly using ORAM to transform a non-oblivious algorithm to oblivious algorithm would incur a logN overhead. It is an open problem to ...
• 366
Is secp256r1 more secure than secp256k1?
Here's a good amount of hard data on a variety of curves, well-analysed and the findings summarised in a readable way: http://safecurves.cr.yp.to/ The article linked from this answer is not nearly ...
• 191
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What is "witness encryption"?
In very short: Assume you have an NP problem, stated as some condition to be met. Since it is a NP condition, the computational complexity to find a satisfying input (called the witness for the ...
• 12.5k
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How to prove that a function is not pseudorandom?
Before answering the actual question, I will offer some general advice. It is important to pay attention, both in class and to the textbook you are reading. If learning how to solve such exercises is ...
• 7,992
Use case for extendable-output functions (XOF) such as SHAKE128/SHAKE256
NIST has yet to standardize any accepted uses for these functions. As they said in response to a comment on the SHA-3 draft (pdf) which questioned this: The text in Section 7 on conformance ...
• 31.8k
Accepted
Where in the FIPS documents is it stated that SHA-1 is not secure?
Much of what NIST publishes about cryptographic algorithms is in Special Publications. In this case it is SP 800-131 (pdf) where they describe transitioning away from old algorithms and key sizes. ...
• 31.8k
Accepted
How does the HOTP dynamic truncation function generalize to longer hashes?
I managed to find it out by reproducing the test vectors. TL;DR: The standard assumes that you use the low 4 bits of the last byte of the hash, regardless of its length. So replace 19 in the original ...
• 31.8k
| 2023-03-24T21:58:28 |
{
"domain": "stackexchange.com",
"url": "https://crypto.stackexchange.com/tags/reference-request/hot",
"openwebmath_score": 0.38545840978622437,
"openwebmath_perplexity": 1779.5884062762602,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Tag Info
Digital signature that is only verifiable by one specific person
What you seem to be looking for is deniable authentication. This is actually a somewhat stronger property than what you're asking for: it guarantees that the recipient (let's call him Bob) cannot ...
• 45.4k
Accepted
Examples of modern, widely used ciphers that suddenly fell?
This question is quite broad by specifying a sudden fall to cryptanalysis and therefore my answer might not be as complete as you wish it to be. If by "become practically attackable, or close enough ...
• 9,889
Is secp256r1 more secure than secp256k1?
The curves secp256r1 and secp256k1 have comparable security. If we consider only the best known attacks today, they have very close security. Both curves are defined over prime fields and have no ...
• 6,744
Accepted
What was NIST’s reason to switch naming from MD… (Message Digest) to SHA… (Secure Hashing Algorithm)?
When NIST introduced SHA-0 in 1993, they – for the first time – switch"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Tag Info
Digital signature that is only verifiable by one specific person
What you seem to be looking for is deniable authentication. This is actually a somewhat stronger property than what you're asking for: it guarantees that the recipient (let's call him Bob) cannot ...
• 45.4k
Accepted
Examples of modern, widely used ciphers that suddenly fell?
This question is quite broad by specifying a sudden fall to cryptanalysis and therefore my answer might not be as complete as you wish it to be. If by "become practically attackable, or close enough ...
• 9,889
Is secp256r1 more secure than secp256k1?
The curves secp256r1 and secp256k1 have comparable security. If we consider only the best known attacks today, they have very close security. Both curves are defined over prime fields and have no ...
• 6,744
Accepted
What was NIST’s reason to switch naming from MD… (Message Digest) to SHA… (Secure Hashing Algorithm)?
When NIST introduced SHA-0 in 1993, they – for the first time – switch"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://blender.stackexchange.com/questions/181659/how-can-i-get-the-total-face-area-of-multiple-meshes
|
# How can I get the Total Face Area of multiple meshes?
In edit mode, there's an overlay option to measure the face area of selected meshes. The problem is when selecting multiple meshes you get the individual face areas for each mesh.
What I'm looking for is a way to sum all face areas to get the total face area.
• I only find an overlay option called Face Area, under the Measurement section of the Overlay pulldown, while in Edit Mode, and it only seems to get the area of single faces. While multiple faces can be selected in Edit Mode, and the area for each shown, I see no way to get an added area even for the faces that make up a single mesh. The wording of your question suggests you were able to find a way to get the total area of the faces of a single mesh, but not a way to get the combined area of the faces from multiple meshes. Were you able to get the total area of a single mesh, and if so, how? – R-800 Jun 7 '20 at 16:34
Total face area of selected meshes
Calculates the total global face area of all mesh objects selected.
Uses bmesh from object to get modifier deforms, and transforms using the world matrix to take into account scale.
import bpy
import bmesh
context = bpy.context
dg = context.evaluated_depsgraph_get()
bm = bmesh.new()
areas = []
for o in context.selected_objects:
if o.type != 'MESH':
continue
bm.from_object(o, dg)
bm.transform(o.matrix_world)
area = sum(f.calc_area() for f in bm.faces)
print(f"{o.name} faces: {len(bm.faces)} area: {area}")
areas.append(area)
bm.clear()
print(f"Total Area: {sum(areas)}")
• Thanks! All I would add is that the numbers it gives are still Metric square meters, even if you change your scene Blender units. If you want Imperial square feet, simply multiply by 10.764. So print(f"Total Area: {sum(areas) * 10.764}") – Coby Randal Jan 15 at 17:58
| 2021-02-27T22:06:03 |
{
"domain": "stackexchange.com",
"url": "https://blender.stackexchange.com/questions/181659/how-can-i-get-the-total-face-area-of-multiple-meshes",
"openwebmath_score": 0.34711652994155884,
"openwebmath_perplexity": 1323.517183634304,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# How can I get the Total Face Area of multiple meshes?
In edit mode, there's an overlay option to measure the face area of selected meshes. The problem is when selecting multiple meshes you get the individual face areas for each mesh.
What I'm looking for is a way to sum all face areas to get the total face area.
• I only find an overlay option called Face Area, under the Measurement section of the Overlay pulldown, while in Edit Mode, and it only seems to get the area of single faces. While multiple faces can be selected in Edit Mode, and the area for each shown, I see no way to get an added area even for the faces that make up a single mesh. The wording of your question suggests you were able to find a way to get the total area of the faces of a single mesh, but not a way to get the combined area of the faces from multiple meshes. Were you able to get the total area of a single mesh, and if so, how? – R-800 Jun 7 '20 at 16:34
Total face area of selected meshes
Calculates the to"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# How can I get the Total Face Area of multiple meshes?
In edit mode, there's an overlay option to measure the face area of selected meshes. The problem is when selecting multiple meshes you get the individual face areas for each mesh.
What I'm looking for is a way to sum all face areas to get the total face area.
• I only find an overlay option called Face Area, under the Measurement section of the Overlay pulldown, while in Edit Mode, and it only seems to get the area of single faces. While multiple faces can be selected in Edit Mode, and the area for each shown, I see no way to get an added area even for the faces that make up a single mesh. The wording of your question suggests you were able to find a way to get the total area of the faces of a single mesh, but not a way to get the combined area of the faces from multiple meshes. Were you able to get the total area of a single mesh, and if so, how? – R-800 Jun 7 '20 at 16:34
Total face area of selected meshes
Calculates the to"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://codereview.stackexchange.com/questions/47471/codility-perm-missing-elem-100-functional-score-but-only-60-performance
|
# Codility - Perm-Missing-Elem: 100% functional score, but only 60% performance
I can not figure out why I didn't get 100% success from the Codility's Perm-Missing-Element test even I solve with $O(n)$. I will appreciate any advice/answers.
You can see the problem, my code, and the scores on the Codility site, as well as here.
## Problem Definition
A zero-indexed array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
class Solution { public int solution(int[] A); }
that, given a zero-indexed array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2
A[1] = 3
A[2] = 1
A[3] = 5
the function should return 4, as it is the missing element.
Assume that:
N is an integer within the range [0..100,000];
the elements of A are all distinct;
each element of array A is an integer within the range [1..(N + 1)].
Complexity:
expected worst-case time complexity is O(N);
expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).
Elements of input arrays can be modified.
## Solution
Here is the code I wrote as an answer.
public class Solution {
public int solution(int[] A) {
int N = A.length + 1;
int total = N * (N + 1) / 2;
for (int i : A) {
total -= i;
}
}
}
-
Doesn't codility provide you more details about this ? Type of test cases for instance – Josay Apr 17 at 13:19
I shared a link which just give a brief test report. They don't share a detailed report. – quartaela Apr 17 at 13:23
Ha ok, I didn't see that. So this is actually a problem of correctness and not of performance. – Josay Apr 17 at 13:44
@chillworld is correct in his observation that the issue is related to the int overflow causing the problems in the performance tests.
The more accurate solution to this is to use a long to set the score, instead of an int.
public class Solution {
public int solution(int[] A) {
long N = A.length + 1;
long total = N * (N + 1) / 2;
for (int i : A) {
total -= i;
}
return (int)total;
}
}
As for your code, I understand why you have variables with names like N and A, because those are the variable names used in the problem.
Those variable names do not conform to standard Java naming conventions though. They should be meaningful names, and start with a lower-case letter, like sum, and data.
the fact that my code below still uses N is not an indication that it is OK .... Do what I say, not what I do...
## Update
Sometimes, the performance tricks in Java can be a PITA.
• Whenever you can, declare your variables as final
• declare your methods as final
• declare variables and for-loop variables as final (if you use the enhanced-for semantics).
• addition may, or may not be faster than subtraction.
Using this code:
class Solution {
public final int solution(final int[] data) {
final long N = data.length + 1;
final long total = (N * (N + 1)) / 2;
long sum = 0L;
for (final int i : data) {
sum += i;
}
return (int)(total - sum);
}
}
Scores 100%
## Update 2 final is not the issue:
public int solution(int[] data) {
long N = data.length + 1;
long total = (N * (N + 1)) / 2;
long sum = 0L;
for (int i : data) {
sum += i;
}
return (int)(total - sum);
}
Also scores 100%
-
believe me I tried that solution which gives the same result :). But variable names doesnt affect performance right ? – quartaela Apr 17 at 13:27
@quartaela - updated answer with 100% solution. – rolfl Apr 17 at 13:37
thanks a lot but I dont get it. How defining variables as final boost the performance from 60 to 100? – quartaela Apr 17 at 13:41
@quartaela - I am pretty convinced your code would have passed with just the long-based arithmetic.... the performance tests were failing, they were not slow. The code above just gives a solution that works in all situations, not just smaller datasets. I will put another test through with the same code, but different final, and see what happens. – rolfl Apr 17 at 13:44
Impressive, it does not do much for my opinion of Java though :\ – konijn Apr 17 at 13:45
From the site :
WRONG ANSWER
got -2147483647 expected 1
So int has overflow because you count everything up. Mine solution to that problem :
public int solution(int[] A) {
int previous = 0;
if (A.length != 0) {
Arrays.sort(A);
for (int i : A) {
if (++previous != i) {
return previous;
}
}
}
return ++previous;
}
result see here : https://codility.com/demo/results/demoS45RNV-37J/
-
Arrays.sort is typically an O(n log n) operation, so it will likely fail the scalability test. – rolfl Apr 17 at 13:23
Did I miss something in the requirements? When I sent an input of int[] A = {26,23,21,24,22};, I did not get the desired result using your method. It could be that I am missing something in the requirement, so please clarify. – Kay Ashton Jul 7 at 3:41
@KayAshton This won't work cause the pre requirement is that you start at 1 (or 2 if 1 is missing). Also you can't have an exact result when you have int[] A = {25,23,21,24,22}; because it could be 20 or 26. – chillworld Jul 7 at 10:33
@rolfl
Changing to long will not fully solve the problem. It only delay the overflow.
I 100% agree your solution when the array is small. My solution require more codes and it works with any inputs. The first method is to sort the array but since we know the array will be like array[i] = i+1 based on the pre-condition, the sorting only took O(2n) at the worst case. And the helper method will loop again just to find the missing number which will take another O(n) time at the worst case. The total is O(3n) which meets the time complexity and since we only modify the input array, the space complexity is O(1).
public static int getMissedNumber(int[] numbers) {
for (int i = 0; i < numbers.length - 1;) {
if (numbers[i] != i + 1 && numbers[i] != 0) {
int position = numbers[i] - 1;
int temp = numbers[position];
numbers[position] = numbers[i];
numbers[i] = temp;
} else {
++i;
}
}
return findMissedNumber(numbers);
}
private static int findMissedNumber(int[] numbers) {
for (int i = 0; i < numbers.length; ++i) {
if (numbers[i] == 0) {
return i + 1;
}
}
return -1;
}
-
| 2014-11-01T04:50:05 |
{
"domain": "stackexchange.com",
"url": "http://codereview.stackexchange.com/questions/47471/codility-perm-missing-elem-100-functional-score-but-only-60-performance",
"openwebmath_score": 0.2675859332084656,
"openwebmath_perplexity": 2733.319700545075,
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"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Codility - Perm-Missing-Elem: 100% functional score, but only 60% performance
I can not figure out why I didn't get 100% success from the Codility's Perm-Missing-Element test even I solve with $O(n)$. I will appreciate any advice/answers.
You can see the problem, my code, and the scores on the Codility site, as well as here.
## Problem Definition
A zero-indexed array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
class Solution { public int solution(int[] A); }
that, given a zero-indexed array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2
A[1] = 3
A[2] = 1
A[3] = 5
the function should return 4, as it is the missing element.
Assume that:
N is an integer within the range [0..100,000];
the elements of A are all distinct;
each element of array A is an integer within the "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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- Engagement: Write with an academic, professional and engaging tone that captivates interest.
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Codility - Perm-Missing-Elem: 100% functional score, but only 60% performance
I can not figure out why I didn't get 100% success from the Codility's Perm-Missing-Element test even I solve with $O(n)$. I will appreciate any advice/answers.
You can see the problem, my code, and the scores on the Codility site, as well as here.
## Problem Definition
A zero-indexed array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
class Solution { public int solution(int[] A); }
that, given a zero-indexed array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2
A[1] = 3
A[2] = 1
A[3] = 5
the function should return 4, as it is the missing element.
Assume that:
N is an integer within the range [0..100,000];
the elements of A are all distinct;
each element of array A is an integer within the "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://www.physicsforums.com/threads/potential-energy-stored-in-hydrostatic-test-unit.760319/
|
# Potential Energy Stored in Hydrostatic Test Unit
1. Jul 2, 2014
### free
I have a pressure vessel of volume V= 1 m^3 . The atmospheric pressure Patm = 101 kPa and Tatm = 22 C. I slowly pump liquid water into the pressure vessel until the internal pressure reaches P1 = 15 MPa. Also, the process is isothermal because the water was pumped in slowly and heat is exchange with the atmosphere. What is the potential energy stored in the tank of water? For example, how much energy could possible be released with the case burst? Assuming the energy stored in the case is negligible.
Last edited: Jul 2, 2014
2. Jul 3, 2014
### Simon Bridge
Good question - how is potential energy normally calculated, in general?
3. Jul 4, 2014
### Baluncore
It is normal to test pressure vessels such as steam boilers with cold water. Healthy cold boilers are not as well behaved as when they are hot. It is critically important that there be very little air present in the vessel being tested since the energy is stored in the gas, with very little stored in the liquid or the vessel walls.
http://en.wikipedia.org/wiki/Compressed_air_energy_storage#Isothermal_storage
4. Jul 4, 2014
### free
How is potential energy normally calculated
I am defining the potential energy as the difference between the total internal energy U2 at (Pmax, Tam) and U1 at (Tatm, Patm). Pmax is the maximum pressure, Tatm is the atmospheric temperature, and Patm is the atmospheric pressure. My first thought was to just look up the internal energy from the compressed liquid water tables since the state is fixed. However, the specific internal energy actually decreases as the pressure is isothermally increased. I must be reading the tables incorrectly because the total internal energy certainly must increase as the pressure increases at a fixed temperature.
5. Jul 4, 2014
### free
Your response does not answer the question and is misleading. Of course, as much air as possible should be evacuated. However, to say that little energy is stored in the liquid or vessel walls is wrong and dangerous. It all depends on the situation. Just look at the strain energy for a long cylinder under pressure $U=\frac{V}{2E} \left(\sigma_\theta^2+\sigma_z^2\right)≈\frac{1.5rtL}{E}\frac{pr}{t}$. If the case has a high strength and low modulus the energy stored in the case can be much larger than that stored in a small pocket of air. My question is about the energy stored in the compressed liquid. I would like to keep the discussion focused on the topic because there are many worked example of the energy store in compressed gas.
6. Jul 4, 2014
### Baluncore
I am sorry to have wrongly interpreted your question. I assumed by isothermal you started with 1m3 of air at 101kPa and compressed it to 15MPa by using water as a liquid piston. From my experience, more than 99% of the energy would then have been stored in the compressed gas. The worked answer to that question was in the wikipedia article I linked. It does not really matter if you extract that energy pneumatically or hydraulically, it is still mostly stored in the gas.
Without a sufficient gas bubble present, the pressures in a closed tank can burst the tank due to daily temperature changes. How much air do you have in your tank when you start to pump in the water? Is it at 101kPa or do you pull a vacuum first?
7. Jul 4, 2014
### AlephZero
If you assume that, you are being inconsistent. If there is no energy stored in the case, it won't break. But since there are no perfectly rigid materials, there always WILL be strain energy stored in the case, and that is what eventually breaks it.
If the casing is strong enough, you can store a lot of energy in the compressed liquid. For example at the deepest point in the ocean (about 10 km) the pressure is about 1000 bar (15,000 psi), and the water volume is compressed by about 5%.
Last edited: Jul 4, 2014
8. Jul 5, 2014
### free
Correction
I forgot to square the stress so the expression for the total strain energy was incorrect. It should be
$U=\frac{V}{2E} \left(\sigma_\theta^2+\sigma_z^2\right)≈\frac{1.25rtL}{E}\frac{p^2r^2}{t^2}$,
which then has the correct units of force times distance.
9. Jul 5, 2014
### free
There is no air in the tank. I first pull a perfect vacuum and pump water into the tank. This is a thought experiment so I can do things like pull a perfect vacuum. Also, there are no temperature changes. As I stated in the problem the process is isothermal.
I am not being inconsistent. I stated as an assumption that the energy stored in the case is negligible so please take it to be true. The reason I made this assumption is not because it is a practical assumption in the "real world", but because it is trivial to calculate the strain energy stored in the case. I only care about the energy stored in the liquid. Further, this is a thought experiment so I can make the young's modulus of the case arbitrarily large and thus make the strain energy in the case approach zero in the limit.
10. Jul 5, 2014
### free
Found the Solution
I would like to thank everyone, especially @Baluncore for their responses. It is great to see people interested in the same topic. I was able to get the correct solution even though I still do not understand the compressed liquid water tables. The solution is found by determining the ideal work it would take to compress the liquid water. The trick of course is knowing the equation of state for the liquid water. I took some searching, but the equation of state and a nice example was given in Fluid Mechanics by Granger.
11. Jan 14, 2016
### ceej
Do you still happen to have the equation for this? Or could you post the two sources you reference for ideal work and the equation of state? Thanks!
12. Jan 14, 2016
### SteamKing
Staff Emeritus
free has been gone from PF for almost 18 months. I wouldn't get my hopes up for a timely response.
13. Jan 16, 2016
### ceej
ah thanks. Does anyone else know a quick source or formula for ideal work to compress water? and the equation of state for water? I am certainly an amateur so if these are complex I may be out of my league....
| 2017-12-16T23:36:34 |
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"domain": "physicsforums.com",
"url": "https://www.physicsforums.com/threads/potential-energy-stored-in-hydrostatic-test-unit.760319/",
"openwebmath_score": 0.6435648798942566,
"openwebmath_perplexity": 531.8202807423274,
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"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161808963631
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Potential Energy Stored in Hydrostatic Test Unit
1. Jul 2, 2014
### free
I have a pressure vessel of volume V= 1 m^3 . The atmospheric pressure Patm = 101 kPa and Tatm = 22 C. I slowly pump liquid water into the pressure vessel until the internal pressure reaches P1 = 15 MPa. Also, the process is isothermal because the water was pumped in slowly and heat is exchange with the atmosphere. What is the potential energy stored in the tank of water? For example, how much energy could possible be released with the case burst? Assuming the energy stored in the case is negligible.
Last edited: Jul 2, 2014
2. Jul 3, 2014
### Simon Bridge
Good question - how is potential energy normally calculated, in general?
3. Jul 4, 2014
### Baluncore
It is normal to test pressure vessels such as steam boilers with cold water. Healthy cold boilers are not as well behaved as when they are hot. It is critically important that there be very little air present in the vessel being tested since the energ"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Potential Energy Stored in Hydrostatic Test Unit
1. Jul 2, 2014
### free
I have a pressure vessel of volume V= 1 m^3 . The atmospheric pressure Patm = 101 kPa and Tatm = 22 C. I slowly pump liquid water into the pressure vessel until the internal pressure reaches P1 = 15 MPa. Also, the process is isothermal because the water was pumped in slowly and heat is exchange with the atmosphere. What is the potential energy stored in the tank of water? For example, how much energy could possible be released with the case burst? Assuming the energy stored in the case is negligible.
Last edited: Jul 2, 2014
2. Jul 3, 2014
### Simon Bridge
Good question - how is potential energy normally calculated, in general?
3. Jul 4, 2014
### Baluncore
It is normal to test pressure vessels such as steam boilers with cold water. Healthy cold boilers are not as well behaved as when they are hot. It is critically important that there be very little air present in the vessel being tested since the energ"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://stats.stackexchange.com/questions/501461/how-to-model-survival-analysis-when-proportional-hazards-assumption-is-not-met-a
|
# How to model survival analysis when proportional hazards assumption is not met and stratification and time-varying are not possible?
I am modelling a survival analysis over a rather long follow-up period (10 years). My exposure is time-invariant and clearly violates the proportional hazards assumptions so Cox Proportional Hazards regression models are not an option. I was wondering about alternatives to conduct my analyses. Please find below some key points:
• Stratification is not possible because it is my main variable of interest that violates the assumption and I need to compare between groups
• Time-varying models are not possible given the nature of my main variable of interest
• I initially thought about time-partitioned model (splitting follow-up time and interacting time with my main variable of interest) but I am not sure that is a good idea because when I plot the KM curves it is all crossing - so I struggle to find a good time interval for splitting
Given these considerations I have thought about employing flexible parametric models. Howevers, from my understanding they make strong assumptions about the shape of the curve - which is something I cannot be certain of. Would a flexible parametric model with restricted cubic spline what I am looking for? But How can I define the number of knots? And how about the distribution?
Could you please provide some inputs and examples? What do you suggest?
I use Stata MP 15 as statistical software
• Have a look for instance here. There are many questions on CV regarding the non-proportionality of hazards issue. I would try an AFT model. You make assumptions about the distribution of the time to event but these assumptions are verifiable. Dec 18 '20 at 14:20
• Thanks. I will look into this. I have been reading about AFT but not entirely clear on how to test the assumption re the underlying hazard curve. Thanks a lot Dec 18 '20 at 14:34
• Is the main variable of interest categorical or continuous?
– EdM
Dec 18 '20 at 15:32
• It is categorical and it does not change over time. It splits the sample into 6 groups. The sample size is fairly large (140k records) so powe is not an issue. Dec 18 '20 at 15:33
• Flexible parametric splines assume a PH or PO model form, if you try the PO (proportional odds) form that could work. Otherwise AFTs are usually the solution if you want to use a 'classical' non-PH model. If you're willing to go non-classical and something more machine learning then try concordance or AFT boosted GBMs, or random survival forests. Dec 18 '20 at 21:52
Before you give up on proportional hazards (PH) modeling, make sure that you aren't relying on group-level Kaplan-Meier survival curves that haven't been adjusted fully for covariates. In particular, I wonder whether there might be some interactions with respect to survival between your main categorical variable of interest and other predictors that could be leading to these results. You seem to have enough data to do some fairly intricate modeling to evaluate those possibilities.
If PH still don't hold, then proportional odds (PO) or accelerated-failure-time (AFT) models would be next steps, as RaphaelS says in a comment. I don't know what's available in Stata for such modeling; otherwise, consider moving to R. The CRAN Survival Task View provides links to several implementations of such modeling approaches, which typically provide tools for examining goodness of fit appropriate to each model type.
Nevertheless, PO and AFT models have their own underlying assumptions. It's possible that your data won't adequately meet any of the PH, PO, or AFT assumptions. In that case, you might have to resort to stratification. That wouldn't necessarily be bad, it would just require more care in presenting results. For example, say that PH held for the other predictors in a Cox model stratified on your 6-level categorical exposure. Yes, there wouldn't be an association of the categorical exposures with event risk that held constant for all times. You could still, however, evaluate the associations of those other predictors with outcome, and compare outcomes among the exposure strata at specific times of interest.
• Thanks. I tried to model the log log plots adjusted for covariates and it was still messy tbh. I am indeed trying to understand how I can test the AFT assumptions using Stata Dec 21 '20 at 10:56
• @Vincent even if you don't end up using R, you might find useful information in some of the package "vignette" files. For PO and AFT modeling, look for example at the flexsurv vignette and the icenReg vignette, as the documents for the standard survival package are pretty much focused on PH models. If you will be doing much difficult survival modeling, learning about those and other R packages would be a good investment of time.
– EdM
Dec 21 '20 at 15:28
I disagree that AFT and PO are necessarily the right next steps. It depends on what you are interested in learning from the model. If you are interested in estimating a hazard ratio, understand that, the idea that there is one hazard ratio that applies over a period of time, implies to some extent that hazards must be proportional.
On the other hand, in many applications there are much more informative summaries of survival analyses than hazard ratios, which don't inherently have a PH assumption baked in. For example, you can calculate risk differences and risk ratios at domain-relevant time-points. These are typically more intuitive and easier to interpret correctly than hazard ratios. RDs and RRs are still available using stratified Cox models (assuming your exposure is categorical). For an overview of these ideas, you can have a look at this reference: https://pubmed.ncbi.nlm.nih.gov/25660080/
Now, if you insist on summarizing your data using hazard ratios, and hazards are not proportional, you can examine how the hazard ratio is changing over time using interactions between time and your time-invariant covariate of interest. This is a valid use of Cox models under non-proportional hazards and can be quite informative - explained in this paper: https://pubmed.ncbi.nlm.nih.gov/12915864/. On the other hand, if the violation of proportionality is not too extreme, a single hazard ratio can still be a reasonable summary of the data - explain in this paper: https://pubmed.ncbi.nlm.nih.gov/32167523/.
| 2021-10-24T06:00:33 |
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"url": "https://stats.stackexchange.com/questions/501461/how-to-model-survival-analysis-when-proportional-hazards-assumption-is-not-met-a",
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|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# How to model survival analysis when proportional hazards assumption is not met and stratification and time-varying are not possible?
I am modelling a survival analysis over a rather long follow-up period (10 years). My exposure is time-invariant and clearly violates the proportional hazards assumptions so Cox Proportional Hazards regression models are not an option. I was wondering about alternatives to conduct my analyses. Please find below some key points:
• Stratification is not possible because it is my main variable of interest that violates the assumption and I need to compare between groups
• Time-varying models are not possible given the nature of my main variable of interest
• I initially thought about time-partitioned model (splitting follow-up time and interacting time with my main variable of interest) but I am not sure that is a good idea because when I plot the KM curves it is all crossing - so I struggle to find a good time interval for splitting
Given these consi"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# How to model survival analysis when proportional hazards assumption is not met and stratification and time-varying are not possible?
I am modelling a survival analysis over a rather long follow-up period (10 years). My exposure is time-invariant and clearly violates the proportional hazards assumptions so Cox Proportional Hazards regression models are not an option. I was wondering about alternatives to conduct my analyses. Please find below some key points:
• Stratification is not possible because it is my main variable of interest that violates the assumption and I need to compare between groups
• Time-varying models are not possible given the nature of my main variable of interest
• I initially thought about time-partitioned model (splitting follow-up time and interacting time with my main variable of interest) but I am not sure that is a good idea because when I plot the KM curves it is all crossing - so I struggle to find a good time interval for splitting
Given these consi"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://datascience.stackexchange.com/questions/40333/adding-more-layers-decreases-accuracy
|
# Adding more layers decreases accuracy
I have my ANN trained on MNIST dataset. Hidden layer has 128 neurons and input layer has 784 neurons. This gave me an accuracy of 94%. However when I added one more layer with 64 neurons in each then the accuracy significantly reduced to 35%. What could be the reason behind this.
Edit : Activation function : sigmoid. 521 epochs.
• What is the activation function you are using? Oct 28 '18 at 11:26
• @DuttaA sigmoid
– Pink
Oct 28 '18 at 12:33
• Could you provide both training and test accuracy in both cases Oct 29 '18 at 15:37
The reason is that by adding more layers, you've added more trainable parameter to your model. You have to train it more. You should consider that MNIST data set is a very easy-to-learn dataset. You can have to layers with much less number of neurons in each layer. Try $$10$$ neurons for each to facilitate the learning process. You can reach to $$100%$$ accuracy.
• It's also a very small dataset. Oct 28 '18 at 12:53
• Yes! $50$ thousand is very smal for deep-learning purposes. Oct 28 '18 at 13:00
• I added 10 neurons in both hidden layers. Trained for 100 epichs and the accuracy is 21%
– Pink
Oct 28 '18 at 17:17
• Epoch or iteration? Oct 28 '18 at 17:40
• Epochs..........
– Pink
Oct 28 '18 at 17:51
The problem in your case (as I thought previously) is the sigmoid activation function. It suffers from many problems. Out of that your performance decrease is likely due to two reasons:
NOTE: The link provided for 'Vanishing Gradient' explains beautifully why increasing layers make your network more susceptible to saturation of learning.
The vanishing gradient problem makes sure your Neural Neyt is trapped in a non optimal solution. While the high learning rate ensures that you get trapped in the non optimal solution. In short the high learning rate after a few oscillations will push your network to saturation.
Solution:
• Best solution is to use the ReLu activation function, with maybe the last layer as sigmoid.
• Decrease the learning rate to $$10^-6$$ to $$10^-7$$ but to compensate increase the number of epochs to $$10^6$$ to $$10^7$$.
• Has nothing to do with this, it's the size of the network compared to the amount of data available. Oct 28 '18 at 13:41
• @MatthieuBrucher what exactly do you mean by size? Oct 28 '18 at 13:43
• The size of the network (number of layers + number of nodes per layers). Oct 28 '18 at 13:43
• @MatthieuBrucher yes adding a layer makes it more prone to less learning via vanishing gradient, check the link of vanishing gradient...i did not add it my answer because the answer given was great, however I will indicate it in my answer Oct 28 '18 at 13:44
• I know what a vanishing gradient is... You don't know what OP uses for the training, and the number of epochs is a proof that you didn't read the question. Oct 28 '18 at 13:46
| 2021-10-19T14:10:02 |
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"domain": "stackexchange.com",
"url": "https://datascience.stackexchange.com/questions/40333/adding-more-layers-decreases-accuracy",
"openwebmath_score": 0.444667786359787,
"openwebmath_perplexity": 660.0628311883436,
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"lm_q1_score": 0.808067204308405,
"lm_q2_score": 0.6187804407739559,
"lm_q1q2_score": 0.5000161808569331
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Adding more layers decreases accuracy
I have my ANN trained on MNIST dataset. Hidden layer has 128 neurons and input layer has 784 neurons. This gave me an accuracy of 94%. However when I added one more layer with 64 neurons in each then the accuracy significantly reduced to 35%. What could be the reason behind this.
Edit : Activation function : sigmoid. 521 epochs.
• What is the activation function you are using? Oct 28 '18 at 11:26
• @DuttaA sigmoid
– Pink
Oct 28 '18 at 12:33
• Could you provide both training and test accuracy in both cases Oct 29 '18 at 15:37
The reason is that by adding more layers, you've added more trainable parameter to your model. You have to train it more. You should consider that MNIST data set is a very easy-to-learn dataset. You can have to layers with much less number of neurons in each layer. Try $$10$$ neurons for each to facilitate the learning process. You can reach to $$100%$$ accuracy.
• It's also a very small dataset. Oct 28 '18 at 12:53
• Ye"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Adding more layers decreases accuracy
I have my ANN trained on MNIST dataset. Hidden layer has 128 neurons and input layer has 784 neurons. This gave me an accuracy of 94%. However when I added one more layer with 64 neurons in each then the accuracy significantly reduced to 35%. What could be the reason behind this.
Edit : Activation function : sigmoid. 521 epochs.
• What is the activation function you are using? Oct 28 '18 at 11:26
• @DuttaA sigmoid
– Pink
Oct 28 '18 at 12:33
• Could you provide both training and test accuracy in both cases Oct 29 '18 at 15:37
The reason is that by adding more layers, you've added more trainable parameter to your model. You have to train it more. You should consider that MNIST data set is a very easy-to-learn dataset. You can have to layers with much less number of neurons in each layer. Try $$10$$ neurons for each to facilitate the learning process. You can reach to $$100%$$ accuracy.
• It's also a very small dataset. Oct 28 '18 at 12:53
• Ye"
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https://www.physicsforums.com/threads/torque-and-friction.110158/
|
# Torque and Friction
1. Feb 10, 2006
### killerdoxie
can friction cause torque?
2. Feb 10, 2006
### SpaceTiger
Staff Emeritus
Do you have any ideas? If I fall off my bicycle and roll down a paved street, what slows down my spinning (and gives me all those bruises)?
3. Feb 10, 2006
### killerdoxie
well, the question was on a test, and we were having a debate in class today about it.
I think no, that friction cannot cause torque, because friction is a reaction, something has to be applied for it to happen. A book sitting by itself does not have friction, but as soon as I push against the book there is friction. The same is true for normal force, I believe, because if i am standing up, the floor pushes back up on me (normal force), but the space two feet in front of me has no normal force since nothing is pushing down on it.
4. Feb 10, 2006
### z-component
But think about the definition of torque. $$\tau = F \times r$$ so under what circumstances could a force cause torque? You're right, forces come in pairs (per Newton's third law) but what makes friction different from any other "applied force" like something pushing against a book?
Last edited: Feb 10, 2006
5. Feb 10, 2006
### killerdoxie
well, since friction is a reactionary force, it doesn't cause the displacement, the other force does, so if r=0, then how can it cause torque?
6. Feb 10, 2006
### z-component
Sorry, but you are incorrect. In SpaceTiger's example, positive torque is undergone while rolling down the hill but the kinetic friction by the ground also causes a torque to counter the positive torque. The torque by friction is negative (positive/negative is ambiguous, but the two torques are in the opposite directions), causing the rotating SpaceTiger's angular acceleration, and therefore velocity, to decrease and eventually become zero.
7. Feb 11, 2006
### Staff: Mentor
Both involve forces, but they are completely separate manifestations of mechanics.
Friction is an undesirable dissipative force encountered where two masses interact, generally by virture of shear forces, i.e. the force is applied parallel with the surface of a solid. Friction occurs in liquids and gases by virtue of atomic collisions and/or adhesion.
See z-components example for torque. Torque is a force applied with a moment.
A net (nonzero) force causes acceleration (or deceleration), while a zero force, i.e. a couple of forces of equal magntide by opposite direction would not provide acceleration, but would provide tensile or compressive loading (and pressure, which = force/area). Similarly, a net nonzero torque produces angular acceleration, while a net zero torque would provide some internal shearing forces (stresses) in a solid object.
As for torque and friction, consider the example of a shaft in a hole (bore). If the static friction exceeds the applied torque, the shaft will not move. Only when the applied torque exceeds the friction between the surfaces of the shaft and bore, will it turn. So in that sense, friction increases the 'required' torque, but does not 'cause' it. The force applied at some distance (moment arm) causes the torque.
| 2017-10-20T08:07:18 |
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"url": "https://www.physicsforums.com/threads/torque-and-friction.110158/",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Torque and Friction
1. Feb 10, 2006
### killerdoxie
can friction cause torque?
2. Feb 10, 2006
### SpaceTiger
Staff Emeritus
Do you have any ideas? If I fall off my bicycle and roll down a paved street, what slows down my spinning (and gives me all those bruises)?
3. Feb 10, 2006
### killerdoxie
well, the question was on a test, and we were having a debate in class today about it.
I think no, that friction cannot cause torque, because friction is a reaction, something has to be applied for it to happen. A book sitting by itself does not have friction, but as soon as I push against the book there is friction. The same is true for normal force, I believe, because if i am standing up, the floor pushes back up on me (normal force), but the space two feet in front of me has no normal force since nothing is pushing down on it.
4. Feb 10, 2006
### z-component
But think about the definition of torque. $$\tau = F \times r$$ so under what circumstances could a force cause torque? "
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# Torque and Friction
1. Feb 10, 2006
### killerdoxie
can friction cause torque?
2. Feb 10, 2006
### SpaceTiger
Staff Emeritus
Do you have any ideas? If I fall off my bicycle and roll down a paved street, what slows down my spinning (and gives me all those bruises)?
3. Feb 10, 2006
### killerdoxie
well, the question was on a test, and we were having a debate in class today about it.
I think no, that friction cannot cause torque, because friction is a reaction, something has to be applied for it to happen. A book sitting by itself does not have friction, but as soon as I push against the book there is friction. The same is true for normal force, I believe, because if i am standing up, the floor pushes back up on me (normal force), but the space two feet in front of me has no normal force since nothing is pushing down on it.
4. Feb 10, 2006
### z-component
But think about the definition of torque. $$\tau = F \times r$$ so under what circumstances could a force cause torque? "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://codedump.io/share/OOfezvdQi6IJ/1/fast-check-for-each-row-in-datatable-if-specific-columns-match-a-criterion
|
swolf - 10 months ago 55
R Question
Fast check for each row in data.table if specific columns match a criterion
I just can't get my head around this quite simple task and reading up on related problems on this site did not help.
I created a minimal example:
a <- data.table(n = c("case1", "case2", "case3"), x = c(0,2,5), y = c(1,1,4), z = c(1,1,0))
cols <- c("x", "y", "z")
a
n x y z
1: case1 0 1 1
2: case2 2 1 1
3: case3 5 4 0
All I want to do is to select all rows from
a
were all values in the columns whose names are saved in
cols
are above 0.
So what I want to get in this case is:
n x y z
2: case2 2 1 1
I used apply in combination with
all()
, but I think there is a much faster way with data.table to do this. My original data is of course much much larger and
cols
contains up 80 column names. Thanks for your help!
We can use Reduce with .SDcols. Specify the columns of interest in .SDcols, loop through the Subset of Data.table (.SD) check whether it is equal 0, get the sum of each row with Reduce, negate (!) to get a logical vector which returns TRUE when there are no 0 elements and use that to subset the rows of 'a'
a[a[, !Reduce(+, lapply(.SD, <=, 0)),.SDcols = cols]]
Or as @Frank mentioned in the comments, pmin can be used as well
a[a[, do.call(pmin, .SD), .SDcols = cols]>0]
| 2017-08-21T01:14:27 |
{
"domain": "codedump.io",
"url": "https://codedump.io/share/OOfezvdQi6IJ/1/fast-check-for-each-row-in-datatable-if-specific-columns-match-a-criterion",
"openwebmath_score": 0.35512202978134155,
"openwebmath_perplexity": 2247.554202358787,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672043084051,
"lm_q2_score": 0.6187804407739559,
"lm_q1q2_score": 0.5000161808569331
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"swolf - 10 months ago 55
R Question
Fast check for each row in data.table if specific columns match a criterion
I just can't get my head around this quite simple task and reading up on related problems on this site did not help.
I created a minimal example:
a <- data.table(n = c("case1", "case2", "case3"), x = c(0,2,5), y = c(1,1,4), z = c(1,1,0))
cols <- c("x", "y", "z")
a
n x y z
1: case1 0 1 1
2: case2 2 1 1
3: case3 5 4 0
All I want to do is to select all rows from
a
were all values in the columns whose names are saved in
cols
are above 0.
So what I want to get in this case is:
n x y z
2: case2 2 1 1
I used apply in combination with
all()
, but I think there is a much faster way with data.table to do this. My original data is of course much much larger and
cols
contains up 80 column names. Thanks for your help!
We can use Reduce with .SDcols. Specify the columns of interest in .SDcols, loop through the Subset of Data.table (.SD) check whether it is equal 0, get th"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"swolf - 10 months ago 55
R Question
Fast check for each row in data.table if specific columns match a criterion
I just can't get my head around this quite simple task and reading up on related problems on this site did not help.
I created a minimal example:
a <- data.table(n = c("case1", "case2", "case3"), x = c(0,2,5), y = c(1,1,4), z = c(1,1,0))
cols <- c("x", "y", "z")
a
n x y z
1: case1 0 1 1
2: case2 2 1 1
3: case3 5 4 0
All I want to do is to select all rows from
a
were all values in the columns whose names are saved in
cols
are above 0.
So what I want to get in this case is:
n x y z
2: case2 2 1 1
I used apply in combination with
all()
, but I think there is a much faster way with data.table to do this. My original data is of course much much larger and
cols
contains up 80 column names. Thanks for your help!
We can use Reduce with .SDcols. Specify the columns of interest in .SDcols, loop through the Subset of Data.table (.SD) check whether it is equal 0, get th"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://www.war-rvr.net/New-York/root-mean-square-error-forecast-accuracy.html
|
Address 305 Orchard St, Vestal, NY 13850 (607) 754-4140
# root mean square error forecast accuracy Newark Valley, New York
The equation for the RMSE is given in both of the references. Sometimes it is hard to tell a big error from a small error. Retrieved 2016-05-17. ^ https://www.otexts.org/fpp/2/5 ^ Erhun, F.; Tayur, S. (2003). "Enterprise-Wide Optimization of Total Landed Cost at a Grocery Retailer". For seasonal time series, a scaled error can be defined using seasonal naïve forecasts: [ q_{j} = \frac{\displaystyle e_{j}}{\displaystyle\frac{1}{T-m}\sum_{t=m+1}^T |y_{t}-y_{t-m}|}. ] For cross-sectional data, a scaled error can be defined as
www.otexts.org. The RMSE will always be larger or equal to the MAE; the greater difference between them, the greater the variance in the individual errors in the sample. Accuracy measures that are based on $e_{i}$ are therefore scale-dependent and cannot be used to make comparisons between series that are on different scales. Although the time series notation has been used here, the average approach can also be used for cross-sectional data (when we are predicting unobserved values; values that are not included in
Hence, the model with the highest adjusted R-squared will have the lowest standard error of the regression, and you can just as well use adjusted R-squared as a criterion for ranking And how do I get around this? So, while forecast accuracy can tell us a lot about the past, remember these limitations when using forecasts to predict the future. ISBN0-471-38108-X. ^ Superintelligence.
The RMSE and adjusted R-squared statistics already include a minor adjustment for the number of coefficients estimated in order to make them "unbiased estimators", but a heavier penalty on model complexity Percentage errors The percentage error is given by $p_{i} = 100 e_{i}/y_{i}$. Hence, if you try to minimize mean squared error, you are implicitly minimizing the bias as well as the variance of the errors. If the RMSE=MAE, then all the errors are of the same magnitude Both the MAE and RMSE can range from 0 to ∞.
As an example of cyclic behaviour, the population of a particular natural ecosystem will exhibit cyclic behaviour when the population increases as its natural food source decreases, and once the population The two most commonly used scale-dependent measures are based on the absolute errors or squared errors: \begin{align*} \text{Mean absolute error: MAE} & = \text{mean}(|e_{i}|),\\ \text{Root mean squared error: RMSE} & = However, there are a number of other error measures by which to compare the performance of models in absolute or relative terms: The mean absolute error (MAE) is also measured in My Google+ profile 1 comment Thoughts?
The forecast for time T + h {\displaystyle T+h} is:[3] y ^ T + h | T = y T + h − k m {\displaystyle {\hat {y}}_{T+h|T}=y_{T+h-km}} where m {\displaystyle That is, it is invalid to look at how well a model fits the historical data; the accuracy of forecasts can only be determined by considering how well a model performs doi:10.1016/0378-7788(91)90028-2. When $h=1$, this gives the same procedure as outlined above. ‹ 2.4 Transformations and adjustments up 2.6 Residual diagnostics › Book information About this bookFeedback on this book Buy a printed
The rate at which the confidence intervals widen is not a reliable guide to model quality: what is important is the model should be making the correct assumptions about how uncertain M.; Lindner, J. R code beer2 <- window(ausbeer,start=1992,end=2006-.1) beerfit1 <- meanf(beer2,h=11) beerfit2 <- rwf(beer2,h=11) beerfit3 <- snaive(beer2,h=11) plot(beerfit1, plot.conf=FALSE, main="Forecasts for quarterly beer production") lines(beerfit2$mean,col=2) lines(beerfit3$mean,col=3) lines(ausbeer) legend("topright", lty=1, col=c(4,2,3), legend=c("Mean method","Naive RMSE method is more accurate.
See also Accelerating change Collaborative planning, forecasting, and replenishment Earthquake prediction Energy forecasting Forecasting bias Foresight (future studies) Futures studies Futurology Kondratiev wave Optimism bias Planning Risk management Scenario planning Spending The only problem is that for seasonal products you will create an undefined result when sales = 0 and that is not symmetrical, that means that you can be much more Again, it depends on the situation, in particular, on the "signal-to-noise ratio" in the dependent variable. (Sometimes much of the signal can be explained away by an appropriate data transformation, before Contents 1 Importance of forecasts 2 Calculating the accuracy of supply chain forecasts 3 Calculating forecast error 4 See also 5 References Importance of forecasts Understanding and predicting customer demand is
By using this site, you agree to the Terms of Use and Privacy Policy. They proposed scaling the errors based on the training MAE from a simple forecast method. Your cache administrator is webmaster. What does it mean?
doi:10.1002/for.3980020411. ^ Cox, John D. (2002). Root mean squared error (RMSE) The RMSE is a quadratic scoring rule which measures the average magnitude of the error. Role thinking: Standing in other people’s shoes to forecast decisions in conflicts. 39: 111–116. ^ "FAQ". This approach can be used with any sort of data where past data is available.
ISBN0-7914-3553-9. MAE and MAPE (below) are not a part of standard regression output, however. Gilchrist, Warren (1976). Production Planning and Inventory Control.
History & Mathematics: Historical Dynamics and Development of Complex Societies. Last but not least, for intermittent demand patterns none of the above are really useful. Feedback This is true too, the RMSE-MAE difference isn't large enough to indicate the presence of very large errors. It is relatively easy to compute them in RegressIt: just choose the option to save the residual table to the worksheet, create a column of formulas next to it to calculate
Greene; J. quantitative methods Qualitative forecasting techniques are subjective, based on the opinion and judgment of consumers, experts; they are appropriate when past data are not available. Operations Research. 51 (3): 343. ISBN0-471-99403-0.
| 2020-01-27T05:16:17 |
{
"domain": "war-rvr.net",
"url": "http://www.war-rvr.net/New-York/root-mean-square-error-forecast-accuracy.html",
"openwebmath_score": 0.7123590707778931,
"openwebmath_perplexity": 1657.4729476617374,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.808067204308405,
"lm_q2_score": 0.6187804407739559,
"lm_q1q2_score": 0.5000161808569331
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Address 305 Orchard St, Vestal, NY 13850 (607) 754-4140
# root mean square error forecast accuracy Newark Valley, New York
The equation for the RMSE is given in both of the references. Sometimes it is hard to tell a big error from a small error. Retrieved 2016-05-17. ^ https://www.otexts.org/fpp/2/5 ^ Erhun, F.; Tayur, S. (2003). "Enterprise-Wide Optimization of Total Landed Cost at a Grocery Retailer". For seasonal time series, a scaled error can be defined using seasonal naïve forecasts: [ q_{j} = \frac{\displaystyle e_{j}}{\displaystyle\frac{1}{T-m}\sum_{t=m+1}^T |y_{t}-y_{t-m}|}. ] For cross-sectional data, a scaled error can be defined as
www.otexts.org. The RMSE will always be larger or equal to the MAE; the greater difference between them, the greater the variance in the individual errors in the sample. Accuracy measures that are based on $e_{i}$ are therefore scale-dependent and cannot be used to make comparisons between series that are on different scales. Although the time"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Address 305 Orchard St, Vestal, NY 13850 (607) 754-4140
# root mean square error forecast accuracy Newark Valley, New York
The equation for the RMSE is given in both of the references. Sometimes it is hard to tell a big error from a small error. Retrieved 2016-05-17. ^ https://www.otexts.org/fpp/2/5 ^ Erhun, F.; Tayur, S. (2003). "Enterprise-Wide Optimization of Total Landed Cost at a Grocery Retailer". For seasonal time series, a scaled error can be defined using seasonal naïve forecasts: [ q_{j} = \frac{\displaystyle e_{j}}{\displaystyle\frac{1}{T-m}\sum_{t=m+1}^T |y_{t}-y_{t-m}|}. ] For cross-sectional data, a scaled error can be defined as
www.otexts.org. The RMSE will always be larger or equal to the MAE; the greater difference between them, the greater the variance in the individual errors in the sample. Accuracy measures that are based on $e_{i}$ are therefore scale-dependent and cannot be used to make comparisons between series that are on different scales. Although the time"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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https://solvedlib.com/mc-5-styles-6-1-what-are-the-basic-concepts-of-a,353525
|
# MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research...
###### Question:
MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research design? 2. What is the difference between experimental, quasi-experimental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative research? È (Ctr) -
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative re- search?
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative re- search?
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| 2023-04-02T00:27:02 |
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"url": "https://solvedlib.com/mc-5-styles-6-1-what-are-the-basic-concepts-of-a,353525",
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"lm_q1q2_score": 0.5000161751761352
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research...
###### Question:
MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research design? 2. What is the difference between experimental, quasi-experimental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative research? È (Ctr) -
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative re- search?
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a g"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research...
###### Question:
MC 5 | Styles 6 | 1. What are the basic concepts of a quantitative research design? 2. What is the difference between experimental, quasi-experimental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative research? È (Ctr) -
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a good one or not? 4. What are the different types of validity in quantitative re- search?
1. What are the basic concepts of a quantitative research de- sign? 2. What is the difference between experimental, quasi-experi- mental, and nonexperimental quantitative studies? 3. How do you know whether a quantitative study is a g"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://physics.stackexchange.com/questions/500167/if-magnetic-force-cant-do-any-work-then-how-can-we-define-a-potential
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# If magnetic force can't do any work, then how can we define a potential?
I am confused about the idea that magnetic forces do no work. If something has a potential, then it has energy and hence can do work. I am using the logic of electric fields for this reasoning. I have seen the mathematical proof of why magnetic fields can't do work but I am not convinced since I can't get the intuition.
• Are you thinking of magnetic scalar or vector potentials? – Emilio Pisanty Sep 4 at 11:00
• Magnetic vector that is B(vector) = Gradient X A(vector) where A is the magnetic potential. – Megha Sep 4 at 11:09
• Valid question since magnetic force is non conservative force – yuvraj singh Sep 4 at 11:18
• Okay, you've got something wrong, $\nabla\times\mathbf A = \mathbf B \ne \nabla\cdot\mathbf A$. – acarturk Sep 4 at 12:26
• @Timetraveler11 The vector potential $\mathbf{A}$ is not a "potential" in the sense that you're defining it. It's certainly like a potential, but it doesn't have all that much to do with energy and work. – probably_someone Sep 4 at 12:41
I am using the logic of electric fields for this reasoning
The magnetic field does not have a potential in the logic of electric fields. In fact, by the logic of electric fields the magnetic field is not even a force field since the magnetic field is not proportional to the force.
The “potential” that a magnetic field has is a vector potential, which is a fundamentally different concept than the potential of the electrostatic field. The scalar potential is directly proportional to the electrostatic potential energy, which is a scalar. The vector potential cannot be proportional to the potential energy since it is not a scalar. So “using the logic of the electric field” simply doesn’t work for the magnetic field.
However, per Poynting’s theorem the magnetic field does have an associated energy density. That field is involved in storing electromagnetic energy at a particular location and also in moving electromagnetic energy from one location to another, but it is not clearly involved in doing work on matter. The term that governs work on matter is $$\mathbf E\cdot \mathbf J$$. But, it is important to realize that these quantities are all closely interrelated. It is possible to write $$\mathbf E\cdot \mathbf J$$ in a way that involves the magnetic field as well.
My favorite derivation of Poynting’s theorem is found at section 11.2 here: http://web.mit.edu/6.013_book/www/book.html In the absence of magnetizable or polarizable material the equation is:
$$-\nabla \cdot (\mathbf E \times \mathbf H) = \frac{\partial}{\partial t} \left(\frac{1}{2}\epsilon_0 \mathbf E \cdot \mathbf E\right) + \frac{\partial}{\partial t}\left(\frac{1}{2} \mu_0 \mathbf H \cdot \mathbf H\right) + \mathbf E \cdot \mathbf J$$
Where the term on the left is the flow of energy from one region of the field to another and the first two terms on the right are the change in the energy density of the electric and magnetic fields respectively. Those are purely field terms; the only term involving an interaction with matter is the last term $$\mathbf E \cdot \mathbf J$$ where $$\mathbf J$$ is the free current. This means that the only way that work can be done on a conductor is via the $$\mathbf E$$ field.
This holds as long as Maxwell's equations hold. So whenever you have a situation that looks like there is a magnetic field doing work, you can always "dig deeper" and find where it is actually the $$\mathbf E$$ field doing the work.
The term $$\mathbf E \cdot \mathbf J$$ includes not only the mechanical work, but also the non-mechanical work. Usually we want to maximize the mechanical work and we want to minimize the non-mechanical work. So suppose, instead of trying to find where the $$\mathbf E$$ field is, we try to separate out the non-mechanical work from the mechanical work.
To do so, we will transform to the rest-frame of the conductor, since in that frame there is no mechanical work so all of the work in that frame is non-mechanical. Assuming that $$v\ll c$$ the transformation equations are: $$\mathbf E' = \mathbf E + \mathbf v \times \mathbf B$$ $$\mathbf J' = \mathbf J - \rho \mathbf v$$ where the primed quantities are quantities in the rest frame of the conductor. Substituting those into $$\mathbf E \cdot \mathbf J$$ and simplifying, we get: $$\mathbf E \cdot \mathbf J = \mathbf E' \cdot \mathbf J' + \mathbf v \cdot (\rho \mathbf E + \mathbf J \times \mathbf B)$$
So, that means that the $$\mathbf E \cdot \mathbf J$$ term itself contains within it the mechanical work due to the magnetic field. If you pull out the non-mechanical work, then the mechanical work is exactly what you would expect from the macroscopic Lorentz force law, including a term from the magnetic field.
This result may seem a little surprising or confusing, as it appears to contradict the above, but it does not. The thing is that all of the fields in electromagnetism are closely related to each other. You can often express the same thing in multiple ways, or dig out hidden dependencies. So although Poynting's theorem holds and although it clearly states that the total work is always $$\mathbf E \cdot \mathbf J$$, it is not a mere coincidence that formulas describing only the mechanical work correctly include the $$\mathbf B$$ field and show that it does mechanical work.
• This seems like something I should know (and maybe I do know it under a different name, or maybe I am just having a "brain fart"), but what exactly is the distinction between mechanical and non-mechanical work? – Aaron Stevens Sep 4 at 13:17
• Mechanical power is $F\cdot v$. It is the work done in the sense of Newton’s laws. Non-mechanical work is other forms of energy transfer, such as Ohmic heating or charging a battery. On a microscopic scale there is no distinction, so non-mechanical work could also be classified by work done on a microscopic scale. – Dale Sep 4 at 13:24
• Ok. Yes I agree with all of that. Thanks! – Aaron Stevens Sep 4 at 13:24
• Thanks, this makes sense now! – Megha Sep 5 at 6:41
• Would you agree with the statement that in case of "no electric Field" the Energy that the conductor gains through the accelleration in the magnetic field stems entirely from the electrons inside being slowed down? Your formula (whose derivation I really like) suggests that. – Quantumwhisp Sep 5 at 20:23
You need to understand that units checking out is just a necessary condition. One can define infinitely many different vector fields over $$\mathbb R^3$$ that has the units of potential. But, this does not imply any of these must be a potential fields. Check this question in math.SE for a mathematical perspective.
Specifically for question in hand, since $$\nabla\times\mathbf A = \mathbf B \ne 0$$ (assuming it is not null), so it follows that this specific field cannot serve as a potential.
Idea of the potential is tied to conservative fields (path independence). Other vector fields don't admit potentials.
The vector potential describes potential momentum per charge unit. A better name would be "momentum potential". The confusion arises when one tries to interpret this quantity as another energy potential.
| 2019-11-19T08:39:41 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# If magnetic force can't do any work, then how can we define a potential?
I am confused about the idea that magnetic forces do no work. If something has a potential, then it has energy and hence can do work. I am using the logic of electric fields for this reasoning. I have seen the mathematical proof of why magnetic fields can't do work but I am not convinced since I can't get the intuition.
• Are you thinking of magnetic scalar or vector potentials? – Emilio Pisanty Sep 4 at 11:00
• Magnetic vector that is B(vector) = Gradient X A(vector) where A is the magnetic potential. – Megha Sep 4 at 11:09
• Valid question since magnetic force is non conservative force – yuvraj singh Sep 4 at 11:18
• Okay, you've got something wrong, $\nabla\times\mathbf A = \mathbf B \ne \nabla\cdot\mathbf A$. – acarturk Sep 4 at 12:26
• @Timetraveler11 The vector potential $\mathbf{A}$ is not a "potential" in the sense that you're defining it. It's certainly like a potential, but it doesn't have all that m"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# If magnetic force can't do any work, then how can we define a potential?
I am confused about the idea that magnetic forces do no work. If something has a potential, then it has energy and hence can do work. I am using the logic of electric fields for this reasoning. I have seen the mathematical proof of why magnetic fields can't do work but I am not convinced since I can't get the intuition.
• Are you thinking of magnetic scalar or vector potentials? – Emilio Pisanty Sep 4 at 11:00
• Magnetic vector that is B(vector) = Gradient X A(vector) where A is the magnetic potential. – Megha Sep 4 at 11:09
• Valid question since magnetic force is non conservative force – yuvraj singh Sep 4 at 11:18
• Okay, you've got something wrong, $\nabla\times\mathbf A = \mathbf B \ne \nabla\cdot\mathbf A$. – acarturk Sep 4 at 12:26
• @Timetraveler11 The vector potential $\mathbf{A}$ is not a "potential" in the sense that you're defining it. It's certainly like a potential, but it doesn't have all that m"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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https://physics.stackexchange.com/questions/162335/what-does-the-statement-the-laws-of-physics-are-invariant-mean/628436
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What does the statement "the laws of physics are invariant" mean?
In the first paragraph of Wikipedia's article on special relativity, it states one of the assumptions of special relativity is
the laws of physics are invariant (i.e., identical) in all inertial systems (non-accelerating frames of reference)
What does this mean? I have seen this phrase several times, but it seems very vague. Unlike saying the speed of light is constant, this phrase doesn't specify what laws are invariant or even what it means to be invariant/identical.
My Question
Can someone clarify the meaning of this statement?
(I obviously know what an inertial frame is)
this phrase doesn't specify what laws are invariant
It doesn't need to since it is a guiding principle, a razor. It is a statement about the nature of physical law.
Put another way, on this principle, an alleged 'physical law' that isn't invariant under inertial coordinate transformations is not a genuine physical law.
or even what it means to be invariant/identical.
Consider, for example
$$\vec F = m \vec a$$
If this equation holds in one coordinate system, it holds in all the coordinate systems related to this one by a Galilean transformation. Thus, it is invariant (unchanged) by this transformation.
• Alfred Centauri: "['The laws of physics are invariant'] is a statement about the nature of physical law. Put another way, on this principle, an alleged 'physical law' that isn't invariant under inertial coordinate transformations is not a genuine physical law." -- In other words: Any assertion which does not involve or refer to any coordinates at all, does, by all appearances, conform to the "nature" of "a genuine physical law". And, arguably, by content, too. "Consider, for example $\vec F = m~\vec a$. If this equation holds in one coordinate system [...]" -- Does it ?? ... Jan 31, 2015 at 8:48
The laws of physics are invariant
means slightly different, but (almost) equivalent things depending on what formulation you are working with.
Given a collection of transformations (a symmetry/transformation group) and a Lagrangian formulation, you can check whether the Lagrangian changes when you apply the transformation. If it does not change (or only by a total derivative), then the action is invariant under the transfomation, and using the principle of extremal action will yield the same equations of motion as before in the sense that they extremalize the same action, and hence describe the exact same system.
Given a collection of transformations and a Hamiltonian formulation, it is of course the Hamiltonian that has to be invariant. The Hamiltonian formalism is not manifestly Lorentz invariant, and it is a bit difficult to use it for relativity, but one can do so. Again, a Hamiltonian unchanging under a transformation induces physically equivalent equations of motion describing the exact same system.
In the case of the statement about inertial frames, the corresponding transformations are given by the Lorentz group $\mathrm{SO}(1,3)$.
• ACuriousMind: "Given a collection of transformations (a symmetry/transformation group)" -- What is thereby supposed to be transformed (what are the "objects of operations")? Surely not "coordinates" (and/or "just subsets of $\mathbb R^n$") ?? Jan 31, 2015 at 8:55
• @user12262: Every object in the Lagrangian (usually these are fields, but they can be coordinates or operators as well) has to transform in a given representation of the transformation group. Specifying the representations is part of giving the transformation. Jan 31, 2015 at 12:57
• ACuriousMind: "[...] Specifying the representations is part of giving the transformation." -- Then let's look specificly at "representations of the Lorentz group" (since your answer suggests specific relevance to the OP's question about "inertial frames"). Now, Wikipedia seems to have quite an extensive page on that topic. However, the word "event" seems to appear on that entire page but once: in the link to Current events. (Hence: I can rest my case.) ... Jan 31, 2015 at 19:11
• @user12262: "Events" are just points in spacetime, which, in special relativity for which the Lorentz group is relevant, is just $\mathbb{R}^{1,3}$ - the fundamental representation of the Lorentz group. This induces that also the (co)tangent vectors transform in the (anti-)fundamental representation, and this linearly extends to the tensor products of them, so every field/form on spacetime also has a natural notion of transforming under the Lorentz group given by it being a tensor of a certain rank. I don't understand what you want. Jan 31, 2015 at 19:32
• ACuriousMind: ""Events" are just points in spacetime" -- No, not "just", but (also) "spacetime coincidences {such as} encounters between two or more material points". "what you want {?}" -- An explicit description how to assign (subsets of) "the fundamental representation of the Lorentz group; just $\mathbb R^{1,3}$" to given sets of encounters between two or more identified "material points"; or at least appreciation for the difficulties involved, since the OP asked about physics. Jan 31, 2015 at 23:01
The laws of physics are the same in every inertial frame of reference.
If the laws differed, that difference could distinguish one inertial frame from the others or make one frame somehow more correct than another. Here are two examples:
Suppose you watch two children playing catch with a ball while the three of you are aboard a train moving with constant velocity. Your observations of the motion of the ball, no matter how carefully done, cant tell you how fast (or whether) the train is moving. This is because Newtons laws of motion are the same in every inertial frame.
Another example is the electromotive force (emf) induced in a coil of wire by a nearby moving permanent magnet. In the frame of reference in which the coil is stationary the moving magnet causes a change of magnetic flux through the coil, and this induces an emf. In a different frame of reference in which the magnet is stationary the motion of the coil through a magnetic field induces the emf. According to the principle of relativity, both of these frames of reference are equally valid. Hence the same emf must be induced in both situations. (Examples are taken from the book ,UNIVERSITY PHYSICS).
According to Einstein:
All our well-substantiated space-time propositions [and consequently, all of our statements concerning facts and findings in physics] amount to the determination of space-time coincidences. If, for example, the [course of events] consisted in the motion of material points, then [...] nothing else are really observable except the encounters between two or more of these material points.
where "determination of space-time coincidences" is thought, at least in principle, to be unambiguously, definitively and consistently obtained by each individual participant.
The statement that
the laws of physics are invariant (i.e., identical) in all inertial systems (non-accelerating frames of reference)
can be understood as a less precise (possibly circular) and more restrictive formulation of Einstein's maxime quoted above. (It is based on Einstein's earliest, preliminary attempts at trying to express his maxime.)
(I obviously know what an inertial frame is)
Really?!? (cmp. "What determines which frames are inertial frames?", PSE/q/3193)
• Lol I stand corrected. I might know what an inertial frame is depending on the context. Jan 30, 2015 at 6:26
• Stan Shunpike: "I might know what an inertial frame is depending on the context." -- Fair enough. But then you ought to make damn sure you know how to recognize and to communicate the context which you want (and which you want anyone else, too) to consider. Jan 30, 2015 at 6:52
In leyman's terms, it just means that the laws of physics are the same everywhere. Here, on the Moon, even in another galaxy, or in a spaceship travelling at near light speed to another galaxy.
• "inertial systems" does not refer to spatial location, but rather to constant velocity. A frame of reference in special relativity extends throughout space and time. (Things are more complicated in general relativity, but that's not what the OP was asking about.) Apr 9, 2021 at 22:36
"The laws of physics are invariant in all inertial systems." is a statement. It's something somebody says to express an idea. Its not an object. An acquaintance who works in a restaurant once said "As long as nobody places any orders, we have everything completely under control." which basically says the exact same thing.
It means more than one thing.
It supports the notion that the laws of physics are only theory. As beautiful and absolute as they may sometimes seem, they do not define reality. They are merely a 'user level' interpretation of it. It being quite possible to successfully work with the laws of physics without understanding them. Nevertheless, their frame is by this statement limited to significantly inertial systems, since reality knows no such thing as a perfectly inertial system. The mentioned significance being something that can be calculated. The laws of physics are by this statement only invariably applicable on systems that can be considered absolutely inertial.
One could say the statement alerts to the fact that outside the realm of significantly inertial systems, the laws of physics will fail to give usable results. It also means that as long as you have a grip on all (significant) dynamic factors in a system, you can count on the laws of physics to give you correct results that express a matching image of the experience of reality, even if you don't fully understand these laws.
It may also tell you, that if you find the laws of physics to apply successfully on a system, meaning any system at all, you're dealing with a (significantly) inertial system, even far outside the realm of physics.
Finally it tells you, that if you find the laws of physics to fail in giving you a matching image of reality and you want to bug-hunt that problem, what you need to look for is an unknown dynamic factor to add to your formulas and thereby to your image of reality.
Any law this does not apply on, is by this statement not to be interpreted as a "Law of Physics." The beauty of it is, that 'true' laws of physics can by the same precondition be successfully applied in fields other than physics.
• Just as a comment: To provide a nice example of how this works, have a look at the answer provided by @Paul. It contains two examples to clarify a point and they do so, but only if regarded as inertial systems. He obviously never actually tried to play catch in a moving train.
– user292922
Apr 10, 2021 at 11:29
"the laws of physics are invariant..."
means that they wouldn't vary or change.
Meaning that any experiment done in one inertial frame would give the same result as the same experiment done in another inertial frame.
It could be any experiment at all, for example, seeing how the momentum of a ball changed if a given force were applied, measuring the angle of the maxima in a diffraction experiment, timing the oscillation of a mass-spring system etc...
Every experiment, if set up the same, would give the same result. Hence two experimenters would deduce the same laws of physics from their experiments.
• what about the doppler effect? Apr 10, 2021 at 13:13
• We experience the doppler effect when the source of a sound is travelling past us e.g. at 200m/s (high frequency changing to low). The experiment has to be set up the same, so if another experimenter on a planet travelling at $0.1c$ relative to us, had air stationary near them and a similar sound source went past them (at 200m/s relative to them), then they would measure the same doppler effect. Apr 10, 2021 at 13:36
• Yes, the experiment has to be done within the inertial frame, as opposed to observing from an inertial frame Apr 10, 2021 at 15:53
• Thank you Stan. Apr 11, 2021 at 16:09
When constructing equations of motion which are the reflection of laws of nature so to speak, we must make them Lorentz invariant and invariant to spacial rotations. This means that they must have the same form under these transformations. One example is construction of a field theory, in which you begin by forming an action which is Lorentz invariant making sure from the very start that you will get it right. Action is a physical quantity with a dimension of Js (joule-second). This quantity is very important for the thing called Hamilton principal of stationary action...So laws of nature same in all inertial reff frames = equations that describe them invariant with form to Lorentz transformations.
In layman's terms, it just means that the laws of physics are the same everywhere. This means that we are talking about one common set of laws. The fun part is figuring out how one common set of laws can behave the same, while they are taking place within different frames of reference. Thus we have a one, that is shared by a many. How can this be, when each frame of reference is different.
Of course once you fully understand both the cause and structure of Special Relativity, the answer becomes obvious.
• Again, reference frames in special relativity aren't about location they're about velocity. Apr 9, 2021 at 22:37
As pointed out by John Hunter the statement means if you done experiment $$A$$ in one inertial frame with velocity $$v$$ and you do the same experiment $$A$$ in another inertial frame with velocity $$v'$$ you will get the same result.
Here we have to be distinguish between realizing an experiment in an inertial and observing a experiment in an inertial frame. As example suppose an inertial frame with velocity $$v$$ measure the frequency of light emitted by source in his lab frame and find it to be $$\nu$$. Another frame with velocity with $$v'$$ with the same source in his lab frame will measure the same frequency $$\nu$$. Now if they are measuring the frequency of another light source in another frame their measurement will be different due to the doppler effect.
• Yes, the experiment should be 'done' in the inertial frame Apr 10, 2021 at 13:45
| 2022-08-11T17:36:06 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"What does the statement "the laws of physics are invariant" mean?
In the first paragraph of Wikipedia's article on special relativity, it states one of the assumptions of special relativity is
the laws of physics are invariant (i.e., identical) in all inertial systems (non-accelerating frames of reference)
What does this mean? I have seen this phrase several times, but it seems very vague. Unlike saying the speed of light is constant, this phrase doesn't specify what laws are invariant or even what it means to be invariant/identical.
My Question
Can someone clarify the meaning of this statement?
(I obviously know what an inertial frame is)
this phrase doesn't specify what laws are invariant
It doesn't need to since it is a guiding principle, a razor. It is a statement about the nature of physical law.
Put another way, on this principle, an alleged 'physical law' that isn't invariant under inertial coordinate transformations is not a genuine physical law.
or even what it means"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"What does the statement "the laws of physics are invariant" mean?
In the first paragraph of Wikipedia's article on special relativity, it states one of the assumptions of special relativity is
the laws of physics are invariant (i.e., identical) in all inertial systems (non-accelerating frames of reference)
What does this mean? I have seen this phrase several times, but it seems very vague. Unlike saying the speed of light is constant, this phrase doesn't specify what laws are invariant or even what it means to be invariant/identical.
My Question
Can someone clarify the meaning of this statement?
(I obviously know what an inertial frame is)
this phrase doesn't specify what laws are invariant
It doesn't need to since it is a guiding principle, a razor. It is a statement about the nature of physical law.
Put another way, on this principle, an alleged 'physical law' that isn't invariant under inertial coordinate transformations is not a genuine physical law.
or even what it means"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://datascience.stackexchange.com/questions/48621/column-with-many-missing-values-36/48632
|
# Column With Many Missing Values (36%)
Hello this is my first machine learning project, I got a dataset with 18.000 rows and I have a column with 4244 values missing.
I don't know why the values are missing since when it's appropriate there's a 0 value in it. The dtype of the column is int64 I consider this column usable and would like to implement it to the model.
Could you please help me with how to deal with this problem, or lead my to a resource to teach me how to deal with this ?
I don't know why the values are missing since when it's appropriate there's a 0 value in it.
The first step is to check with some SME (Subject Matter Expert) or the Data Custodian. I can't tell you how many times I've built a model/started analysis just to figure out that the data was wrong. Try to figure out the reason behind the Nulls/0.
Besides that there are many ways to handle missing data a few are below:
• Remove records with this missing value in your column. If this is an important column to your model it may be best to get rid of that record depending on the shape (rows x cols/features) of your dataset. Don't throw off the results of your model because there's some data that may throw it off (even if you use some of the methods below)
• Mean/Median/Mode Impute - A common method of handling missing data is to fill the missing values with the column's mean or median (rarely do you use the Mode).
• Fill the values that creates a normal distribution - it depends on your data, but filling the values so you get normally distributed column data can be beneficial
• Try all these methods and more - When you start modeling you'll learn to "throw stuff at the wall" and see what sticks. Look at your model results, talk with SMEs, and think about what makes sense. Some ways of handling missing data will work better with different models/datasets. Experiment and have fun!
What you want to do is called imputation of missing values. There are some different strategies. Commonly you use the column mean, median or a value that serves as a good default.
If you are using a Pandas DataFrame then you can do:
Replace with 0
df = df.fillna(0)
Replace with column mean
df = df.fillna(np.mean())
Replace with column median
df = df.fillna(np.median())
If you are using numpy you could do:
Replace with 0
X = np.nan_to_num(X)
Replace with mean
col_mean = np.nanmean(X, axis=0)
inds = np.where(np.isnan(X))
X[inds] = np.take(col_mean, inds[1])
Replace with median
col_median = np.nanmedian(X, axis=0)
inds = np.where(np.isnan(X))
X[inds] = np.take(col_median, inds[1])
If you want some reading: imputation strategies
• So it's ok to just fill the column with nan values even if theres gonna be so many of them? – dungeon Apr 4 '19 at 17:21
• Not necessarily a good idea. Usually it is a good starting point to figure out the meaning of the variables and then decide about things like this. – Michael M Apr 4 '19 at 17:54
• I agree with @MichaelM. The zero was based on " it's appropriate there's a 0 value in it" which made me think you already decided on that as a default. I updated my answer with some more options. – Simon Larsson Apr 4 '19 at 17:57
| 2020-05-25T02:57:40 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Column With Many Missing Values (36%)
Hello this is my first machine learning project, I got a dataset with 18.000 rows and I have a column with 4244 values missing.
I don't know why the values are missing since when it's appropriate there's a 0 value in it. The dtype of the column is int64 I consider this column usable and would like to implement it to the model.
Could you please help me with how to deal with this problem, or lead my to a resource to teach me how to deal with this ?
I don't know why the values are missing since when it's appropriate there's a 0 value in it.
The first step is to check with some SME (Subject Matter Expert) or the Data Custodian. I can't tell you how many times I've built a model/started analysis just to figure out that the data was wrong. Try to figure out the reason behind the Nulls/0.
Besides that there are many ways to handle missing data a few are below:
• Remove records with this missing value in your column. If this is an important column"
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Here's an extract from a webpage:
"# Column With Many Missing Values (36%)
Hello this is my first machine learning project, I got a dataset with 18.000 rows and I have a column with 4244 values missing.
I don't know why the values are missing since when it's appropriate there's a 0 value in it. The dtype of the column is int64 I consider this column usable and would like to implement it to the model.
Could you please help me with how to deal with this problem, or lead my to a resource to teach me how to deal with this ?
I don't know why the values are missing since when it's appropriate there's a 0 value in it.
The first step is to check with some SME (Subject Matter Expert) or the Data Custodian. I can't tell you how many times I've built a model/started analysis just to figure out that the data was wrong. Try to figure out the reason behind the Nulls/0.
Besides that there are many ways to handle missing data a few are below:
• Remove records with this missing value in your column. If this is an important column"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://www.physicsforums.com/threads/chemical-kinetics.449647/
|
# Chemical kinetics
## Main Question or Discussion Point
So, let's say we have an elementary reaction:
2A --> C
The rate of this reaction is (according to IUPAC: http://goldbook.iupac.org/R05156.html)
$$- \frac{1}{2} \frac{d[A]}{dt} = k [A]^2$$
If we integrate this we get a certain integrated rate law (second order)
However, if we multiply all of the stoichiometric coefficients by 2:
4A --> 2C
And do the same procedure, we'll get a different rate law, right?
Does this mean that the stoichiometric coefficients should be taken as the smallest possible integers in a rate equation? I can't find this statement anywhere. Help me understand this if you can.
Last edited:
Borek
Mentor
Same problem with equilibrium (reaction quotient) - depending on the stoichiometric coefficients you will get different values for equilibrium constant. Nothing wrong with that - that's an obvious consequence of different representation of the process. However, if everyone uses different representation of the process, it is difficult to compare results. To avoid that we use - as an accepted convention - smallest possible integer coefficients in reaction equations. Always.
Now, it doesn't mean you can't use fractions during balancing, or even when doing stoichiometry problems, when only ratio counts, but when presenting your results it is always better to follow the convention. It makes communication easier.
Same problem with equilibrium (reaction quotient) - depending on the stoichiometric coefficients you will get different values for equilibrium constant. Nothing wrong with that - that's an obvious consequence of different representation of the process. However, if everyone uses different representation of the process, it is difficult to compare results. To avoid that we use - as an accepted convention - smallest possible integer coefficients in reaction equations. Always.
Now, it doesn't mean you can't use fractions during balancing, or even when doing stoichiometry problems, when only ratio counts, but when presenting your results it is always better to follow the convention. It makes communication easier.
Yes, that's exactly what I though. Thank you so much. I was having this argument with some people who are supposed to know this stuff, but I didn't find a place where this stuff was actually written.
Ygggdrasil
| 2020-08-07T01:58:52 |
{
"domain": "physicsforums.com",
"url": "https://www.physicsforums.com/threads/chemical-kinetics.449647/",
"openwebmath_score": 0.7092809081077576,
"openwebmath_perplexity": 619.9299830205692,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
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"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.5000161751761352
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Chemical kinetics
## Main Question or Discussion Point
So, let's say we have an elementary reaction:
2A --> C
The rate of this reaction is (according to IUPAC: http://goldbook.iupac.org/R05156.html)
$$- \frac{1}{2} \frac{d[A]}{dt} = k [A]^2$$
If we integrate this we get a certain integrated rate law (second order)
However, if we multiply all of the stoichiometric coefficients by 2:
4A --> 2C
And do the same procedure, we'll get a different rate law, right?
Does this mean that the stoichiometric coefficients should be taken as the smallest possible integers in a rate equation? I can't find this statement anywhere. Help me understand this if you can.
Last edited:
Borek
Mentor
Same problem with equilibrium (reaction quotient) - depending on the stoichiometric coefficients you will get different values for equilibrium constant. Nothing wrong with that - that's an obvious consequence of different representation of the process. However, if everyone uses different representation"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Chemical kinetics
## Main Question or Discussion Point
So, let's say we have an elementary reaction:
2A --> C
The rate of this reaction is (according to IUPAC: http://goldbook.iupac.org/R05156.html)
$$- \frac{1}{2} \frac{d[A]}{dt} = k [A]^2$$
If we integrate this we get a certain integrated rate law (second order)
However, if we multiply all of the stoichiometric coefficients by 2:
4A --> 2C
And do the same procedure, we'll get a different rate law, right?
Does this mean that the stoichiometric coefficients should be taken as the smallest possible integers in a rate equation? I can't find this statement anywhere. Help me understand this if you can.
Last edited:
Borek
Mentor
Same problem with equilibrium (reaction quotient) - depending on the stoichiometric coefficients you will get different values for equilibrium constant. Nothing wrong with that - that's an obvious consequence of different representation of the process. However, if everyone uses different representation"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://www.acmerblog.com/hdu-2662-coin-4254.html
|
2014
02-12
# Coin
Moon has many coins, but only contains two value types which is 5 cents and 7 cents, Some day he find that he can get any value which greater than 23 cents using some of his coins. For instance, he can get 24 cents using two 5 cents coins and two 7 cents coins, he can get 25 cents using five 5 cents coins, he can get 26 cents using one 5 cents coins and three 7 cents coins and so on.
Now, give you many coins which just contains two value types just like Moon, and the two value types identified by two different prime number i and j. Can you caculate the integer n that any value greater than n can be created by some of the given coins.
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by a single space.(2<=i<=1000000, 2<=j<=1000000)
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by a single space.(2<=i<=1000000, 2<=j<=1000000)
1
5 7
23
#include <iostream>
using namespace std;
typedef unsigned long long int longint;
int main()
{
int t;
cin >> t;
while (t--)
{
longint n, m;
cin >> n >> m;
longint ans;
ans = (n * m) - n - m;
cout << ans << endl;
}
return 0;
}
// end
// ism
1. 有一点问题。。后面动态规划的程序中
int dp[n+1][W+1];
会报错 提示表达式必须含有常量值。该怎么修改呢。。
2. 5.1处，反了；“上一个操作符的优先级比操作符ch的优先级大，或栈是空的就入栈。”如代码所述，应为“上一个操作符的优先级比操作符ch的优先级小，或栈是空的就入栈。”
| 2017-01-17T04:50:51 |
{
"domain": "acmerblog.com",
"url": "http://www.acmerblog.com/hdu-2662-coin-4254.html",
"openwebmath_score": 0.5008339881896973,
"openwebmath_perplexity": 1409.1119708952224,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080672135527632,
"lm_q2_score": 0.6187804196836383,
"lm_q1q2_score": 0.500016169534767
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"2014
02-12
# Coin
Moon has many coins, but only contains two value types which is 5 cents and 7 cents, Some day he find that he can get any value which greater than 23 cents using some of his coins. For instance, he can get 24 cents using two 5 cents coins and two 7 cents coins, he can get 25 cents using five 5 cents coins, he can get 26 cents using one 5 cents coins and three 7 cents coins and so on.
Now, give you many coins which just contains two value types just like Moon, and the two value types identified by two different prime number i and j. Can you caculate the integer n that any value greater than n can be created by some of the given coins.
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by a single space.(2<=i<=1000000, 2<=j<=1000000)
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"2014
02-12
# Coin
Moon has many coins, but only contains two value types which is 5 cents and 7 cents, Some day he find that he can get any value which greater than 23 cents using some of his coins. For instance, he can get 24 cents using two 5 cents coins and two 7 cents coins, he can get 25 cents using five 5 cents coins, he can get 26 cents using one 5 cents coins and three 7 cents coins and so on.
Now, give you many coins which just contains two value types just like Moon, and the two value types identified by two different prime number i and j. Can you caculate the integer n that any value greater than n can be created by some of the given coins.
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by a single space.(2<=i<=1000000, 2<=j<=1000000)
The first line contains an integer T, indicates the number of test cases.
For each test case, there are two different prime i and j separated by"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://gmatclub.com/forum/in-the-figure-vertex-q-of-square-opqr-is-on-circle-with-centre-o-if-271054.html
|
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# In the figure, vertex Q of square OPQR is on circle with centre O. If
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In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
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19 Jul 2018, 21:55
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In the figure, vertex Q of square OPQR is on circle with centre O. If the area of the square is 8, what is the area of the circle?
A. $$8 \pi$$
B. $$8 \sqrt{2} \pi$$
C. $$16 \pi$$
D. $$32 \pi$$
E. $$64 \pi$$
Attachment:
figure 11.jpg [ 14.68 KiB | Viewed 367 times ]
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In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
### Show Tags
19 Jul 2018, 22:08
1
vertex Q of square OPQR is on circle with centre O
=> radius of the circle = diagonal of the square
area of square is $$a^2$$ = 8
=> a = $$2\sqrt{2}$$
diagonal of the square = $$\sqrt{a^2 + a^2}$$
=> diagonal = $$\sqrt{8 + 8}$$
=> diagonal = $$\sqrt{16}$$ = 4
=> radius of the circle = 4
=> Area of the circle = $$4^2 \pi$$ = $$16 \pi$$
Hence option C
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Re: In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
### Show Tags
19 Jul 2018, 23:28
Bunuel wrote:
In the figure, vertex Q of square OPQR is on circle with centre O. If the area of the square is 8, what is the area of the circle?
A. $$8 \pi$$
B. $$8 \sqrt{2} \pi$$
C. $$16 \pi$$
D. $$32 \pi$$
E. $$64 \pi$$
Attachment:
figure 11.jpg
OA:C
As per figure,Diagonal ($$diagonal_{square}$$) of Square is equal to Radius of circle.
Area of Square = $$\frac{1}{2}*Diagonal_{square}^2=8$$
$$Diagonal_{square}^2=16$$;
As $$Diagonal_{square}$$ = Radius of circle
$${Radius}^2 =16$$
Area of circle= $$\pi *$$ $${Radius}^2=\pi*16$$
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Re: In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
### Show Tags
19 Jul 2018, 23:32
Bunuel wrote:
In the figure, vertex Q of square OPQR is on circle with centre O. If the area of the square is 8, what is the area of the circle?
A. $$8 \pi$$
B. $$8 \sqrt{2} \pi$$
C. $$16 \pi$$
D. $$32 \pi$$
E. $$64 \pi$$
Attachment:
figure 11.jpg
Note :
Area of the square = 1/2 $$(d)^2$$
Given
1/2*$$(d)^2$$ = 8
d = 4.
Now diagonal has become the radius of the of circle.
Area of the circle = pie * $$r^2$$
= 16 pie.
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Re: In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
### Show Tags
20 Jul 2018, 02:13
+1 for C.
Area of the Square = L^2 = 8
L = 2 root 2
Diagonal of the Square = D
D^2 = (2root2)^2 + (2root2)^2
D^2 = 16
D = 4 = Radius of the circle
Area of the Circle = (Radius)^2*pi = (4^2)pi = 16 pi
Hence, C.
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Re: In the figure, vertex Q of square OPQR is on circle with centre O. If &nbs [#permalink] 20 Jul 2018, 02:13
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# In the figure, vertex Q of square OPQR is on circle with centre O. If
## Events & Promotions
Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.
| 2018-09-24T12:11:38 |
{
"domain": "gmatclub.com",
"url": "https://gmatclub.com/forum/in-the-figure-vertex-q-of-square-opqr-is-on-circle-with-centre-o-if-271054.html",
"openwebmath_score": 0.6726136207580566,
"openwebmath_perplexity": 6542.005548507336,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080671950640465,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.500016169455907
}
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# In the figure, vertex Q of square OPQR is on circle with centre O. If
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In the figure, vertex Q of square OPQR is on circle with centre O. If [#permalink]
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Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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# In the figure, vertex Q of square OPQR is on circle with centre O. If
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### HideShow timer Statistics
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Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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http://flashcodehacks.com/please-help/could-you-please-help-me-with-this-matter.html
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## Contents
It got me so confused while trying it that I've been working on it for 2 weeks. Phy How do you find the derivative of #y=arcsin(1/x)#? Opportunities for recent engineering grads. Ana The supergiant star Betelgeuse has a measured angular diameter of 0.044 arcsecond.
It was "four times as many minutes past three o'clock", four times what? –Morgan Rodgers Aug 11 '16 at 9:06 @Morgan Rodgers What I've given was the exact question. Hence $x=3+\frac13$. Answer A minute ago What is the temperature at the point where the ... contest-math puzzle word-problem share|cite|improve this question edited Aug 11 '16 at 9:26 asked Aug 11 '16 at 8:19 Nagendra 1257 1 I don't know about the rest of the users, http://www.algebra.com/algebra/homework/Linear-equations/Linear-equations.faq.question.6410.html
Reload the page to see its updated state. and beyond What's Next Socratic Meta Scratchpad Ask question Log in Sign up Statistics Science Anatomy & Physiology Astronomy Astrophysics Biology Chemistry Earth Science Environmental Science Organic Chemistry Physics Math Algebra share|cite|improve this answer edited Aug 11 '16 at 9:48 answered Aug 11 '16 at 9:42 barak manos 35.8k43481 How did you get x+10? I,m so thankful for still being here but I,m not really just the motions thank you and hear my plee Sep 20, 2015 Need releace by: Anonymous It seems that no
Are you trying to show a difference for the before and after of when the index changed? If I assume that it is 'x' minutes to 6 o' clock then it is 180-x past 3 o' clock and 50 minutes ago it was 130-x past 3 o' clock. Please? Start with a one sentence answer Then teach the underlying concepts Don't copy without citing sources How to add symbols & How to write great answers preview ?
Answer 5 minutes ago How do you find all rational zeroes of the ... Or are you just trying to control for the change over? I know God knew already what I burden and worries now. https://www.facebook.com/business/help/community/question/?id=10151767855613711 Answer Write a one sentence answer...
Rates of return? Answer 4 minutes ago What is the angle between #<-2,7,-1> # and ... SOLUTION: Could you please help me solve this problem. Why hardware division takes much longer than multiplication How to destroy a Palantír What was Admiral Ackbar's name?
## Please Solve This Math Problem
Org What types of cells do not undergo mitosis? It got me so confused while trying it that I've been working on it for 2 weeks. Could You Please Help Me With This Matter Lee · Texas A&M University Central Texas Simply put, there is no rule against using a dummy variable in a GARCH model. Please Solve This Issue Sebastian MajewskiI am going to estimate to volatility market index with GARCH model.Best regards,Khurshid Apr 3, 2016 Kevin K.
For i thank you for every day, secound, hour and minute in my life and i ask you to send the holy spirit into everyone that is in need of your You don't use $5000 because that is the inital investment (this is where I messed up originally). At the end of the year, her investment had grown to$5531. Answer 5 minutes ago The number of trout in a lake drops when the lake ... Could You Please Help Me With This Issue
c. #1# student is not taking any of the subjects. History World History ... I have attached .txt file for the same. Join for free An error occurred while rendering template.
Forgive me in the bad evil that I done to him . Answer 17 seconds ago What is the derivative of #ln(sinx^2)#? On the other hand, if the dummy variable is the variable of interest, then I would suggest also running alternative methods.
## Thanks to R^2 for his assistance!
Please try the request again. This equation is = to 531 because that is the profit received from the % of the two accounts. Sign up today to join our community of over 11+ million scientific professionals. Eng How does astrometry work?
It got me so confused while trying it that I've been working on it for 2 weeks. share|cite|improve this answer answered Aug 11 '16 at 8:58 Faijal Turiya 1 But it wasn't mentioned there that 4 times as many minutes to 6 o' clock but it Are you trying to show a change in volatility before and after the change over or are you modeling for other purposes like forecasting? U.S I no longer have PC and internet access at home to make regular contributions every day on Socratic ...
Please explain to me as per the meaning of the question which of the above equations is correct?
| 2017-09-22T11:45:33 |
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"url": "http://flashcodehacks.com/please-help/could-you-please-help-me-with-this-matter.html",
"openwebmath_score": 0.3741207718849182,
"openwebmath_perplexity": 1439.161408197329,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.8080671950640465,
"lm_q2_score": 0.6187804337438501,
"lm_q1q2_score": 0.500016169455907
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"## Contents
It got me so confused while trying it that I've been working on it for 2 weeks. Phy How do you find the derivative of #y=arcsin(1/x)#? Opportunities for recent engineering grads. Ana The supergiant star Betelgeuse has a measured angular diameter of 0.044 arcsecond.
It was "four times as many minutes past three o'clock", four times what? –Morgan Rodgers Aug 11 '16 at 9:06 @Morgan Rodgers What I've given was the exact question. Hence $x=3+\frac13$. Answer A minute ago What is the temperature at the point where the ... contest-math puzzle word-problem share|cite|improve this question edited Aug 11 '16 at 9:26 asked Aug 11 '16 at 8:19 Nagendra 1257 1 I don't know about the rest of the users, http://www.algebra.com/algebra/homework/Linear-equations/Linear-equations.faq.question.6410.html
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It got me so confused while trying it that I've been working on it for 2 weeks. Phy How do you find the derivative of #y=arcsin(1/x)#? Opportunities for recent engineering grads. Ana The supergiant star Betelgeuse has a measured angular diameter of 0.044 arcsecond.
It was "four times as many minutes past three o'clock", four times what? –Morgan Rodgers Aug 11 '16 at 9:06 @Morgan Rodgers What I've given was the exact question. Hence $x=3+\frac13$. Answer A minute ago What is the temperature at the point where the ... contest-math puzzle word-problem share|cite|improve this question edited Aug 11 '16 at 9:26 asked Aug 11 '16 at 8:19 Nagendra 1257 1 I don't know about the rest of the users, http://www.algebra.com/algebra/homework/Linear-equations/Linear-equations.faq.question.6410.html
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Molecular Orbital Diagram of O2, F2, and Ne2 Molecules. The unhybridized 2p1 orbital lies perpendicular to the three hybridised orbitals. What is the molecular orbital energy diagram of co. What is the atomic and molecular orbital diagram of f2. Molecular orbital diagram for carbon dimer c2. Molecular … One of the molecular orbitals in this molecule is constructed by adding the mathematical functions for the two 1s atomic orbitals that come together to form this molecule. F2 molecular orbital diagram. Molecular Term Symbols 15th May 2008 I. The LUMO (lowest unoccupied molecular orbital) and HOMO (highest occupied molecular orbital) of difluoride's MO diagram help explain why the molecule is very stable - the diagram also tells us that the bond order is 1. Here is the solution, > * For O2 molecule, > * For F2 molecule, Thanks for reading. Bond order = 1/2[Nb-Na], where, Nb=no. Write Electronic Configuration Of N2 And O2 Mot. Diagram shows pair of electrons spins daytonva150. Molecular orbital diagram for b2. A molecular orbital diagram or mo diagram is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals lcao method in particular. F2 molecular orbital diagram. Energy. When two (or more) atomic orbitals overlap to make a bond we can change our perspective to include all of the bonded atoms and their overlapping orbitals. BO = (Σ(bonding electrons) - … Be as specific in your explanation as you can. l = 0 2. As an exercise please fill electrons in the molecular orbitals of a relative energy level diagram to derive and confirm the above conclusion as well as the conclusion regarding the cef2 molecule. Diamagnetic paramagnetic ni co 4 cn 2 and nicl4 iit f2 mo diagram for nicn4 a diagram is shown at the bottom left of horizontal line a calculated mo diagram for f2 six 2p orbitals three from each atom combine to produce one sigma bonding orbital two pi and their corresponding antibonding. The bond order is 1/2(no. Energy level diagram for Molecular orbitals. HOMO stands for highest unoccupied molecular orbital and LUMO stands for the lowest unoccupied molecular orbital. If we put all of the molecular orbitals of ethyne together, in a single energy diagram, it would look as follows. A draw the molecular orbital diagram. In the formation of HF molecule ,only 2p electrons of fluorine atom would combine effectively with the solitary electron of hydrogen atom. This video explains the molecular orbital theory, rules for writing the ele... Molecular Orbital Theory - Part 2. You have 3 valence electrons from each boron minus 1 for the positive charge. The atomic orbitals combine to produce the following molecular orbital diagram: Comparison of the above energy level diagram wit hthat for nitrogen - you can see that the 2s g level lies lower than p u. If you use the Aufbau process to populate the sigma, pi, pi*, and sigma* orbitals of these species, you will find that F2+ has bond order 1.5, F2 has bond order 1.0, and F2- has bond order 0.5. Therefore, we can describe an electron in an atom as occupying an atomic orbital, or by a wave function Ψ. Ne2 molecular orbital diagram. A bonding mo shows a build up of electron density between the two positively charged nuclei. Best Riding Lawn Mower Under 1500 Best Lawn Mower Under Dollar... En gage parking brake. Molecular orbital diagram of Li2 & Be2: Number of electrons in Li2 molecule =6. This can be seen qualitatively in the first figure here. Information from the MO diagram justify O2's stability and show that it's bonding order is 2. A) F2; B) F2^2+ C) Ne2^2+ D) O2^2+ E) F2^2-2) Use molecular orbital diagrams to determine which of the following are paramagnetic. When you draw out a molecular orbital diagram for F2, you will see that the last orbital electrons occupy is the π*2p orbital, which makes it the highest occupied molecular orbital. A fundamental principle of these theories is that as atoms bond to form molecules a certain number of atomic orbitals combine to form the same number of. The same method can be applied to other diatomic molecules, but involving more than the 1s atomic orbitals. 1 answer belt diagram. Consider the h 2 molecule for example. This scheme of bonding and antibonding orbitals is usually depicted by a molecular orbital diagram such as the one shown here for the dihydrogen ion H 2 +. Visit the post for more. Identify All Indicated Structures And Ear Regions ... Tractor Trailer Pre Trip Inspection Diagram, In The Circular Flow Diagram Firms Produce, Prokaryotic Cells Vs Eukaryotic Cells Venn Diagram, Husqvarna Riding Mower Carburetor Diagram, 1996 Jeep Cherokee Serpentine Belt Diagram, Troy Bilt 4 Cycle Trimmer Carburetor Diagram, 2003 Chevy Cavalier Exhaust System Diagram. According to the Molecular Orbital Theory, individual atoms combine to form molecular orbitals. Calculate the bond order and magnetic behavior. Explain why the relative energy levels diagrams for Li2, Be2, B2, C2, N2 are different The molecular orbital theory of Li2 to F2 gives a graphical explanation. Diamagnetic paramagnetic ni co 4 cn 2 and nicl4 iit f2 mo diagram for nicn4 a diagram is shown at the bottom left of horizontal line a calculated mo diagram for f2 six 2p orbitals three from each atom combine to produce one sigma bonding orbital two pi and their corresponding antibonding. Atomic valence electrons (shown in boxes on the left and right) fill the lower-energy molecular orbitals before the higher ones, just as is the case for atomic orbitals. The net contribution of the electrons to the bond strength of a molecule is identified by determining the bond order that results from the filling of the molecular orbitals by electrons. How to graph a mo molecular orbital diagram for f2. 3. what is the bond order for O2. 5 years ago. Ne2 Molecular Orbital Diagram Mo Bonding In F2 And O2 Chemistry Ne2 Molecular Orbital Diagram The Molecular Picture Of Amplified Diatomic Species Mo Theory Chemogenesis Molecular Orbital Diagram Ne2 2 Awesome Chemistry Archive October 28 Share this post. What Are Antioxidants What Do They Do How Do. Molecular orbitals mo are constructed from atomic orbitals. This mo is called the bonding orbital and its energy is lower than that of the original atomic orbitals. of electrons in bonding molecular orbital and Na= no. Molecular Structure Atomic Orbitals. F2 2 molecular orbital diagram. A linear combination of properly oriented atomic orbitals for the formation of sigma s and pi p bonds. Everyday Chemistry. Show show your work or give a brief explanation of the process. Thus designation of this orbital diagram is MO. Related Videos. What is the atomic and molecular orbital diagram of f2. 2. what is the bond order for F2 . A simple approach to molecular orbital (MO) theory for heterogeneous diatomic molecules is to show the energy level diagram. Briggs And Stratton Pressure Washer Carburetor Dia... 2018 Freightliner Cascadia Fuse Box Diagram, 2004 Chevy Avalanche Radio Wiring Diagram, Ford 2000 Tractor Ignition Switch Wiring Diagram, 2004 Jeep Grand Cherokee Radio Wiring Diagram. F2 molecular orbital diagram. The nodal plane of the molecular orbitals in the electronic configuration of the molecule is defined as the plane where the zero probability of the electrons is seen. Simple Molecular Orbitals - Sigma and Pi Bonds in Molecules An atomic orbital is located on a single atom. Ii b 2 and predict bond order and magnetic properties. Explain your answer. This shows two unpaired electrons in π2px and π2pz. 1. the number … Answer Save. Molecular orbital diagram for f2. Representation of sp 2 hybridization sp 2 hybridization is also known as trigonal hybridisation. Newer Post Older Post Home. Fig 3 molecular orbital diagrams energy levels of molecular orbitals for a n2 and b o2 f2. Molecular Orbital Diagram F2 — UNTPIKAPPS Ne2 molecular orbital diagram mo bonding in f2 and o2 chemistry libretexts what is the molecular orbital diagram of o2 and f2 quora there are simple generic mo diagrams for diatomic molecules published online such as mo s for 2nd row diatomic molecules both oxygen and fluorine have. And the molecular orbital diagram is ne2 molecular orbital diagram luxury energy level diagrams hydrogen hypothetical 3 idealized mo diagram bonding in o2 f2 and ne2. Legal. 000 A B C 88 Oder D E F 0 0 0 0 0 0 . The molecular orbital diagram for an o 2 molecule would therefore ignore the 1s electrons on both oxygen atoms and concentrate on the interactions between the 2s and 2p valence orbitals. A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) method in particular. Molecular orbital energy level of Li2. 2. the total numbers of electrons in the pi*2p molecular orbitals of F2 is. Explanation: According to these principles, molecular orbitals are filled in order of increasing energy. The organic chemistry tutor 569143 views. Also find its bond order and magnetic character? Molecular orbital Diagram F2. This is a common picture of a p x orbital This simplifi ed p x orbital is often useful. Serpentine belt diagram for 2008 pontiac g6 this pontiac g6 belt diagram is for model year 2008 with v6 35 liter eng... Craftsman lt 1500 drive belt diagram. For the ion f2. For the second period elements, the 2s and 2p orbitals are important for MO considerations. The relative energies of the sigma orbitals drop below that of the pi orbitals. Related Videos. Quantum mechanics uses higher mathematics to … The effective nuclear charge increases to the right of the period, stabilizing the 2s orbital more drastically than the 2p orbital. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. https://chem.libretexts.org/@app/auth/2/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FPhysical_and_Theoretical_Chemistry_Textbook_Maps%2FSupplemental_Modules_(Physical_and_Theoretical_Chemistry)%2FChemical_Bonding%2FMolecular_Orbital_Theory%2FMO_bonding_in_F2_and_O2, information contact us at [email protected], status page at https://status.libretexts.org. c. Do you expect F2+ to be paramagnetic or diamagnetic? The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Molecular orbital diagram of N 2 BO = [Nb-Na] = [10-4] = 3 Since all the electrons in nitrogen are paired, it is diamagnetic molecule. Draw The Molecular Orbital Diagram Of O2 Or N2. Molecular orbital diagram for n2 o2 c2 f2 also h2o. A bare molecular orbital diagram is presented and you must drag the correct orbitals and labels onto the diagram. Molecular orbital diagram for b2. The orbital diagram for a diatomic molecule is to find the bond order add the 15 electrons in the molecular orbitals the blue colored energy levels in the diagram one at a time until you have used them up. Hybridization of atomic orbitals sigma and pi bonds sp sp2 sp3 organic chemistry bonding duration. Molecular orbital theory build f2 duration. Two electrons in the same orbital cannot have the same set of all four quantum numbers identical. In The Diagram Which Multicell Structure Is Diploi... How To Make A Venn Diagram On Google Slides, Troy Bilt 21 Self Propelled Mower Parts Diagram. Governor throttle spring setup on 35 h briggs. A fundamental principle of these theories is that as atoms bond to form molecules, a certain number of atomic orbitals combine to form the same number of molecular … Molecular orbital diagram of b2. They also give insight to the bond order of the … In o 2 and f 2 there is a crossover of the sigma and the pi ortbials. Use the molecular orbital diagram shown to determine which of the following is most stable based on their bond order Atomic orbitals Molecular orbitals Atomic orbitals O, F2, Nez • Nez2 • F₂2. In chemistry, a molecular orbital is a mathematical function describing the location and wave-like behavior of an electron in a molecule.This function can be used to calculate chemical and physical properties such as the probability of finding an electron in any specific region. Molecular orbitals are bonding when the orbital phase considerations are favourable. The f2 ion has one more valence electron or 15. 0. the total numbers of electrons in the pi2p molecular orbital of B2 is. Bond Order of O2, F2, N2 respectively are _____ a) +1, +2, +3 b) +2, +3, +1 c) +2, +1, +3 d) +3, +2, +1 Answer: c Explanation: Bond Order=[[Number of electrons in bonding molecular … Answers to molecular orbitals problem set 1. Hybridization of atomic orbitals sigma and pi bonds sp sp2 sp3 organic chemistry bonding duration. F2 molecular orbital diagram. Answer to: Which of the following orbitals in F2 has one nodal plane that contains both nuclei? Using the molecular orbital diagram, calculate the bond order of F2+. Molecular orbitals are obtained … Molecular orbital diagram for f2. In the 2p orbitals we have three lower (in energy) bonding orbitals: 1 sigma, and 2 pi orbital, for the first bond is a single bond (sigma), the second is a pi bond (pi) and the third is also pi (pi). F2 molecular orbital diagram. Additionally i labelled the humo as pi2py and the lumo as sigma2px. Bond Order. F2 molecular orbital diagram. Li2 = σ1s2,σ*1s2,σ2s2. 2008 vw passat 20t fuse box diagram 2008 vw passat 20t fuse box map fuse panel layout diagram parts. Following Diatomic Omonuclear Molecules H2 B2 C2 N2 O2 Ne2 Calculate bond order for simple molecules. They completely fill all the orbitals except. y x z y x z Use … Convert and download youtube videos to … Figure 12. A molecular orbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals (LCAO) method in particular. Use the molecular orbital diagram shown to determine which of the following is most stable based on their bond order Atomic orbitals Molecular orbitals Atomic orbitals O, F2, Nez • Nez2 • F₂2. This shows the MO diagrams for each homonuclear diatomic molecule in the second period. Subscribe to: Post Comments … Tricky chemistry basics. Our first lesson about MO diagrams was today and I was taken through an example with $\ce{F2}$ as shown below: but one thing that the lecturer did not explain, and I couldn't find over the internet with explanation, was the notation $\ce{3\sigma _g}$, $\ce{1\pi _u}$, $\ce{1\pi _{g}^{*}}$ and $\ce{3\sigma _{u}^{*}}$. Solved a prepare molecular orbital energy level diagram for. Term Symbols for Molecules: Applying MO Diagrams Excitations between molecular electronic states provide information about properties of molecules. Molecular orbitals mo are constructed from atomic orbitals. Molecular orbital diagram for n2 o2 c2 f2 also h2o. diagram; the MOs go between them. Hybridization of atomic orbitals sigma and pi bonds sp sp2 sp3 organic chemistry bonding duration. • F2 022 • F22 Many home security providers offer motion sensitive cameras with infrared night vision but the tenvis wireless surveillance camera balances... Honda 350 rancher. molecular orbital mo diagram of n2 molecular orbital diagram for nitrogen gas n2 use aufbau and hund to fill with 10 valence electrons you sigma2s 2 sigma2s 2 pi2p 4 mo diagram for n2 molecular orbital there are two mo diagrams you need to memorize for diatoms n2 o2 ne2 etc e is for the elements up to nitrogen the other is for after N2 2- Molecular orbital Diagram. Do you expect this to have a shorter or longer bond length than F2? The electronic configuration for cef2 is. Draw the molecular orbital diagram of N 2. We know that we can consider electrons as either particle or wave nature. Abhinav jha btech dual computer science engineering indian institute of technology dhanbad 2022 answered feb 3 2018 author has 85 answers and 266k answer views. B.O = 1. Convert and download youtube videos to … Molecular Orbital Theory - Part 1. Explain your answer. molecular orbital theory build f2 for the ion f2 a draw the molecular orbital diagram b calculate the bond order c would this ion exist d write the electron molecular orbital theory c2 n2 o2 and f2 molecules this video shows the mo diagrams of the c2 n2 o2 and f2 molecules 6)Li2. In o 2 and f 2 there is a crossover of the sigma and the pi ortbials. The bond lengths are inverse to the bond order (e.g. b. Favorite Answer. Molecular orbitals (MO) are constructed from atomic orbitals. Consider the h 2 molecule for example. Watch the recordings here on Youtube! F2+ molecular orbital diagram. This video is about mo diagram 2 f2. Answered by | 13th Jun, 2016, 04:45: PM. May 25, By Mrs Shilpi Nagpal 9 . Relevance. Briggs and stratton governor spring. A molecular orbital diagram or mo diagram is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecular orbital theory in general and the linear combination of atomic orbitals lcao method in particular. Consider the MO diagram for Li2. a double bond is shorter than a single bond), so the order is F2+ < F2 < F2- from shortest to longest. Missed the LibreFest? F2 o2 and f2 o2 and b2 o2. If we put all of the molecular orbitals of ethyne together, in a single energy diagram, it would look as follows. Please label your answers a-c and place them on separate lines. Energy level diagram for Molecular orbitals. And the molecular orbital diagram is ne2 molecular orbital diagram luxury energy level diagrams hydrogen hypothetical 3 idealized mo diagram bonding in o2 f2 and ne2. A hand drawn version does not have to be exact. 7. It's a little hard to give a decent answer as you need to see a molecular orbital diagram. The first ten molecular orbitals may be arranged in order of energy as follow: σ (1s) <σ ∗ (1s) < σ(2s) <σ ∗ (2s) < π(2p x) = π(2p y) < σ(2p z) < π ∗ (2p x) =π ∗ (2p y) <π ∗ ( 2p z) Relationship between electronic configuration and Molecular behaviour. This shows two unpaired electrons in π2px and π2pz. Between N2 and O2, the order of the orbitals … The f2 ion has one more valence electron or 15. A diatomic molecular orbital diagram is used to understand the bonding of a diatomic molecule. Answer to question 1 by drawing molecular orbital diagrams for b2 c2 n2 o2 and f2 predict which of these homonuclear diatomi. Mo'jizakor ayol 84 Premyera uzbek o'zbek tilida. The bonding mo wave function ψ psi can be squared ψ 2 psi squared to represent electron density. - YouTube Mo'jizakor ayol 84 Premyera uzbek o'zbek tilida. One of the molecular orbitals in this molecule is constructed by adding the mathematical functions for the two 1s atomic orbitals that come together to form this molecule. Draw the lewis structure of pf 3a how many share. 1. what is the bond order for C2. 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Explain your answer. A molecular orbital diagram or mo … The molecular orbitals depicted below are derived from 2p atomic orbitals in F2+. Downloads Valence Molecular Orbital Diagram For Nitrogen Vs Oxygen . Please label your answers a-c and place them on separate lines. The bonding mo wave function ψ psi can be squared ψ 2 psi squared to represent electron density. In O2 and F2, there is a crossover of the sigma and the pi ortbials: the relative energies of the sigma orbitals drop below that of the pi orbitals'. The size of the effect depends on the 2s 2p energy difference. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. Explain why the relative energy levels diagrams for Li2, Be2, B2, C2, N2 are different The molecular orbital theory of Li2 to F2 gives a graphical explanation. Chemistry molecular structure 44 of 45 molecular orbital theory bond order 3 h to ne duration. F2 2 molecular orbital diagram. By drawing molecular orbital diagrams for b2 c2 n2 o2 and f2 predict which of these homonuclear diatomic molecules are magnetic. A) F2; B) F2^2+ C) Ne2^2+ D) O2^2+ E) F2^2-2) Use molecular orbital diagrams to determine which of the following are paramagnetic. A) O2^2-B) Ne2^2+ C) O2^2+ D) F2^2+ E) None of the above are paramagnetic; 3) Draw the molecular orbital diagram needed, and determine which of the following is paramagnetic. To further demonstrate the consistency of the lewis structures with mo. This is a bond between two lithium atoms, … Give bond order and predict whether they are diamagnetic or paramagnetic for all the molecules above question 1 3. σ2 1sσ21sσ22sσ22sπ22pπ22p n2 14 e. D write the electron configuration of the ion. The other molecular orbital produced s h h shows a decrease in electron density between the nuclei reaching a value of zero at the midpoint between the nuclei where there is a nodal plane. The molecular orbital theory (MO) has been introduced for the diatomic hydrogen molecules. We have to answer the following questions. B.O =(Nb- Na). C. Do you expect this to have a shorter or longer bond length than F2 2.. Bond lengths are inverse to the bond becomes a pi bond π bond the... Them on separate lines have 3 valence electrons from each boron atom … a bonding MO wave function ψ can... Panel layout diagram parts give insight to the bond order and magnetic properties your as. Youtube videos to … molecular orbital diagram for n2 O2 c2 F2 also h2o the... Where, Nb=no https: //status.libretexts.org consistency of the molecular orbital diagram for Ne2 '' a. Positively charged nuclei Ne2 2+ F2 2- O2 2+ Ne2 2+ F2 2+ F2 seen qualitatively in figure... Electronic of hydrogen atom atom would combine effectively with the solitary electron of hydrogen atom Do they Do how.... The humo as pi2py and the LUMO as sigma2px important for MO considerations orbital more drastically than 1s... Video explains the applications of molecular orbital diagram for Li2 we can an. Unpaired electrons in π2px and π2pz Honda isnt snorkeled am i just my! Or give a brief explanation of the original atomic orbitals sigma and the pi ortbials σ2 1sσ21sσ22sσ22sπ22pπ22p n2 14 D! Are diamagnetic or paramagnetic for all the molecules above question 1 3 F2. Number … the electronic of hydrogen and fluorine are 1s¹ and 1s²2s²2p⁵ respectively the relative energies of orbitals... Of cn 1 1525057, and Ne2 molecules constructed from atomic orbitals unpaired electrons in bonding molecular diagram! F2+ < F2 < F2- from shortest to longest shows a build up of electron density between the positively! Valence electron or 15 s and pi bonds sp sp2 sp3 organic chemistry bonding duration 1... … F2 2 molecular orbital diagram of F2 a bonding MO shows build! Sigma s and pi p bonds involving more than the 1s atomic orbitals 1 ) draw lewis. Your MO diagrams for each homonuclear diatomic molecule in the pi2p molecular orbital diagrams for b2 co. what is atomic! F2 2+ F2 is a common picture of a diatomic molecule the effective charge! Previous National Science Foundation support Under grant numbers 1246120, 1525057, and Ne2 molecules 2.! Electrons of an atom are present in various atomic orbitals sigma and bonds! Antibonding orbitals a bare molecular orbital theory ( MO ) are constructed from atomic orbitals in.... The three hybridised orbitals the diagram the second period order of F2+ ], where, Nb=no between lithium! For O2 molecule, only 2p electrons of an atom are present in various atomic orbitals order magnetic. Jan 16 2009 is also known as trigonal hybridisation build up of electron between... Organic chemistry bonding duration a p x orbital this simplifi ed p x orbital located. Squared ψ 2 psi squared to represent electron density represents an antibonding MO of sidewise overlapping of 2p-orbital...... Electron or 15 molecular structure 44 of 45 molecular orbital and LUMO stands for unoccupied!, 1525057, and 1413739 minus 1 for the second period elements, 2s. 2006 Honda rancher 350 F... Posted on jan 16 2009 and b O2 F2 crossover the... Show show your work or give a brief explanation of the following has the highest bond order of.! To further demonstrate the consistency of the original atomic orbitals figure here sigma s and pi p bonds diagram.... The first figure here: Applying MO diagrams for b2 of sidewise of. An electron in F2+, 0 unpaired molecular orbital diagram of f2 in the same set of four. And 2p orbitals are bonding when the orbital phase considerations are favourable providers offer motion sensitive with. Orbital this simplifi ed p x orbital is located on a single bond ), so the is... Energy level diagram for involving more than the 2p orbital to add bonding to most above pool!, it would look as follows bare molecular orbital diagram for for molecules: Applying MO diagrams for each diatomic! Valence electrons from each boron minus 1 for the second period a brief explanation the... The 2p orbital molecules is to show the energy level diagram a shorter or longer bond length than F2 involving... 2P atomic orbitals you have 3 valence electrons from each boron minus 1 for the of! Hybridization sp 2 hybridization is also known as trigonal hybridisation and antibonding orbitals According to these orbitals as molecular of... F2, and Ne2 molecules period as the effective nuclear charge increases atomic! 1 3 to molecular orbital energy diagram of F2 Comments … molecular orbital diagram is presented and must., LibreTexts content is licensed by CC BY-NC-SA 3.0 to ne duration bonding orbital! Levels of molecular orbital diagram of O2 or n2 associated with several nuclei diagram in predicts the thing... The figure below O2, F2, and 1413739 plane that contains both?. A brief explanation of the following has the highest bond order of increasing energy increases to right... O2S stability … F2 molecular orbital theory bond order of F2+ box map fuse panel layout diagram parts night but. Add bonding to most above ground pool pumps answered by | 13th Jun, 2016 04:45. For molecules: Applying MO diagrams to work out the number of in! Does not have to give the orbital correlation diagram in predicts the same set of all four quantum numbers....
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"Molecular Orbital Diagram of O2, F2, and Ne2 Molecules. The unhybridized 2p1 orbital lies perpendicular to the three hybridised orbitals. What is the molecular orbital energy diagram of co. What is the atomic and molecular orbital diagram of f2. Molecular orbital diagram for carbon dimer c2. Molecular … One of the molecular orbitals in this molecule is constructed by adding the mathematical functions for the two 1s atomic orbitals that come together to form this molecule. F2 molecular orbital diagram. Molecular Term Symbols 15th May 2008 I. The LUMO (lowest unoccupied molecular orbital) and HOMO (highest occupied molecular orbital) of difluoride's MO diagram help explain why the molecule is very stable - the diagram also tells us that the bond order is 1. Here is the solution, > * For O2 molecule, > * For F2 molecule, Thanks for reading. Bond order = 1/2[Nb-Na], where, Nb=no. Write Electronic Configuration Of N2 And O2 Mot. Diagram shows pair of electrons spins daytonva150. Molecular o"
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"Molecular Orbital Diagram of O2, F2, and Ne2 Molecules. The unhybridized 2p1 orbital lies perpendicular to the three hybridised orbitals. What is the molecular orbital energy diagram of co. What is the atomic and molecular orbital diagram of f2. Molecular orbital diagram for carbon dimer c2. Molecular … One of the molecular orbitals in this molecule is constructed by adding the mathematical functions for the two 1s atomic orbitals that come together to form this molecule. F2 molecular orbital diagram. Molecular Term Symbols 15th May 2008 I. The LUMO (lowest unoccupied molecular orbital) and HOMO (highest occupied molecular orbital) of difluoride's MO diagram help explain why the molecule is very stable - the diagram also tells us that the bond order is 1. Here is the solution, > * For O2 molecule, > * For F2 molecule, Thanks for reading. Bond order = 1/2[Nb-Na], where, Nb=no. Write Electronic Configuration Of N2 And O2 Mot. Diagram shows pair of electrons spins daytonva150. Molecular o"
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# In the above figure , Triangle ACD is inscribed in the circle
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In the above figure , Triangle ACD is inscribed in the circle. if side BD = 6 and CD = 10, What is the circumference of the circle?
A)8.5 $$\pi$$
B)10.5 $$\pi$$
C)12.5$$\pi$$
D)14$$\pi$$
E)16$$\pi$$
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 09:51
Can anyone explain this pls?
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 09:56
Abhi077 wrote:
Attachment:
GC.png
In the above figure , Triangle ACD is inscribed in the circle. if side BD = 6 and CD = 10, What is the circumference of the circle?
A)8.5 $$\pi$$
B)10.5 $$\pi$$
C)12.5$$\pi$$
D)14$$\pi$$
E)16$$\pi$$
is it D
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:05
It's C. Solved by trigonometry and Pythagoras theorem
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In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:08
1
$$BC^2 = 10^2 - 6^2 = 8$$
Let AB = k
In ADC , $$AD^2 = (8+k)^2 - 10^2$$
In ADB , $$AD^2 = 6^2 + k^2$$
$$(8+k)^2 - 10^2 = 6^2 + k^2$$
k = 4.5
Diameter = 8+4.5 = 12.5
Circumference = 12.5π
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In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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Updated on: 17 Oct 2018, 10:18
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I did an approximation in this question(After an unsuccessful previous attempt)
We can calculate BC as 8, because triangle DBC is a right angled triangle.
Now join a line parallel to DC making a rectangle AECD. Join the diagonal DE.
Since in a rectangle diagonals bisect each other, length of OC will be approximately 6(if you can visualize this in the figure)
OC as radius will give circumference as approximately 12 π
Let me know if this approach is lacking in some way.
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:16
Abhi077 wrote:
Attachment:
GC.png
In the above figure , Triangle ACD is inscribed in the circle. if side BD = 6 and CD = 10, What is the circumference of the circle?
A)8.5 $$\pi$$
B)10.5 $$\pi$$
C)12.5$$\pi$$
D)14$$\pi$$
E)16$$\pi$$
As the inscribed angle is 90 degree, AC is the diameter of the circle.
In triangle DBC
since angle B is right angle
(10)2= (6)2+ (BC)2
BC= 8
Triangle ADB and BDC are similar( Why)
In triangle ADC angle C is (90-x)
so In triangle BDC, angle D is X
hence,
AC= 25/2
AC is the diameter, so 2R=25/2
R=25/4
So Circumference= 2*pie*25/4
=12.5 pie
C
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:23
pandeyashwin wrote:
$$BC^2 = 10^2 - 6^2 = 8$$
Let AB = k
In ADC , $$AD^2 = (8+k)^2 - 10^2$$
In ADB , $$AD^2 = 6^2 + k^2$$
$$(8+k)^2 - 10^2 = 6^2 + k^2$$
k = 4.5
Diameter = 8+4.5 = 12.5
Circumference = 12.5π
How did you get AB=8? I understand BC=8
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:28
We first find BC:
\sqrt{100-36}=\sqrt{64}=8
Now we can find AB. We know that:
We also know that:
Replacing AD^2 in the second equation, we got:
AB^2+36+100=64+AB^2+16*AB --> AB=4
So we can now calculate the diameter AC, which is AB+BC=12
The circumference is 12pi
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink]
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17 Oct 2018, 10:28
Imhotese8991 wrote:
pandeyashwin wrote:
$$BC^2 = 10^2 - 6^2 = 8$$
Let AB = k
In ADC , $$AD^2 = (8+k)^2 - 10^2$$
In ADB , $$AD^2 = 6^2 + k^2$$
$$(8+k)^2 - 10^2 = 6^2 + k^2$$
k = 4.5
Diameter = 8+4.5 = 12.5
Circumference = 12.5π
How did you get AB=8? I understand BC=8
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Actually never, I think it was just a system error.
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Re: In the above figure , Triangle ACD is inscribed in the circle [#permalink] 17 Oct 2018, 10:28
| 2020-07-06T21:48:54 |
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# In the above figure , Triangle ACD is inscribed in the circle
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# In the above figure , Triangle ACD is inscribed in the circle
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https://www.physicsforums.com/threads/inviscid-flow-and-viscous-flow.262602/
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# Inviscid flow and viscous flow
1. Oct 8, 2008
### jason.bourne
viscous flows are always rotational because of shear stress that is exerted on the fluid element due to viscosity.
what about the inviscid flows? can they be rotational ? if yes then what are the factors which makes the inviscid flows rotational?
2. Oct 8, 2008
### minger
By rotational do you mean have vorticity? If so then yes, in fact the fundamental equations can be written in terms of vorticity rather than velocity by taking the curl of the equations.
$$\frac{D\omega}{Dt} = \omega \cdot \nabla u + \nu \nabla^2 \omega$$
Last edited: Oct 8, 2008
3. Oct 8, 2008
### jason.bourne
okay fine but what is it that is making it to rotate?
like in viscous flows its the shear stress that causes the rotation of the fluid element.
4. Oct 8, 2008
### minger
Anything. Don't think of vorticity as a whirlpool in your bathtub; any time the flow turns even a little bit, it has vorticity.
5. Oct 9, 2008
### jason.bourne
viscous flows are always rotational because of the shear stress exerts a rotational moment about the center of the element .
what about the inviscid flows? what causes rotation in an inviscid flows?
shear stress is absent. The only forces acting on the fluid element are pressure force and weight. Weight acts through COG, pressure acts normal to the element surface, neither can cause rotation , then what is causing rotation in inviscid flows?
i dont think it can just rotate at its own wish. There has to be something right?
6. Sep 12, 2010
### FireBones
You may want to look up Helmholtz's third theorem.
7. Sep 12, 2010
When using inviscid flow, usually a point vortex is added to the model to simulate the vorticity present in an actual viscous flow (for example, the trailing edge of an airfoil). Vorticity is conserved in potential flow, so you have to introduce it somewhere in order for the flow to make sense in real problems. That sort of highlights the problem with potential flow; you can't fully model viscous phenomena with inviscid flow, and the real world is viscous.
8. Dec 21, 2010
### Nick RT
Hey Jason,
I don't know know whether you've figured out your answer by now or not but I'll give you mine. This is a good question and here's how it works.
Consider solid body rotation of a fluid. Viscous forces are negligible but what causes the fluid particles to rotate is the pressure gradiant in the normal direction to the streamlines. There is no moment acting on the particles but each fluid particle rotates as it moves along the streamlines. I hope it makes sense if you need more help send me an email [email protected]
| 2017-03-27T14:56:52 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Inviscid flow and viscous flow
1. Oct 8, 2008
### jason.bourne
viscous flows are always rotational because of shear stress that is exerted on the fluid element due to viscosity.
what about the inviscid flows? can they be rotational ? if yes then what are the factors which makes the inviscid flows rotational?
2. Oct 8, 2008
### minger
By rotational do you mean have vorticity? If so then yes, in fact the fundamental equations can be written in terms of vorticity rather than velocity by taking the curl of the equations.
$$\frac{D\omega}{Dt} = \omega \cdot \nabla u + \nu \nabla^2 \omega$$
Last edited: Oct 8, 2008
3. Oct 8, 2008
### jason.bourne
okay fine but what is it that is making it to rotate?
like in viscous flows its the shear stress that causes the rotation of the fluid element.
4. Oct 8, 2008
### minger
Anything. Don't think of vorticity as a whirlpool in your bathtub; any time the flow turns even a little bit, it has vorticity.
5. Oct 9, 2008
### jason.bourne
vi"
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- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# Inviscid flow and viscous flow
1. Oct 8, 2008
### jason.bourne
viscous flows are always rotational because of shear stress that is exerted on the fluid element due to viscosity.
what about the inviscid flows? can they be rotational ? if yes then what are the factors which makes the inviscid flows rotational?
2. Oct 8, 2008
### minger
By rotational do you mean have vorticity? If so then yes, in fact the fundamental equations can be written in terms of vorticity rather than velocity by taking the curl of the equations.
$$\frac{D\omega}{Dt} = \omega \cdot \nabla u + \nu \nabla^2 \omega$$
Last edited: Oct 8, 2008
3. Oct 8, 2008
### jason.bourne
okay fine but what is it that is making it to rotate?
like in viscous flows its the shear stress that causes the rotation of the fluid element.
4. Oct 8, 2008
### minger
Anything. Don't think of vorticity as a whirlpool in your bathtub; any time the flow turns even a little bit, it has vorticity.
5. Oct 9, 2008
### jason.bourne
vi"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://gmatclub.com/forum/what-is-the-value-of-b-c-143682.html
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# What is the value of b + c ?
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What is the value of b + c ?
(1) ab + cd + ac + bd = 6
(2) a + d = 4
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Re: What is the value of b + c ? [#permalink]
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06 Dec 2012, 05:10
What is the value of b + c ?
(1) ab + cd + ac + bd = 6 --> $$(ab+bd)+(cd+ac)=6$$ --> $$b(a+d)+c(a+d)=6$$ --> $$(a+d)(b+c)=6$$ --> if $$a+d=1$$, then $$b+c=6$$ but if $$a+d=6$$, then $$b+c=1$$. Not sufficient.
(2) a + d = 4. Nothing about $$b$$ and $$c$$. Not sufficient.
(1)+(2) From (1) we have that $$(a+d)(b+c)=6$$ and from (2) we have that $$a + d = 4$$, thus $$4(b+c)=6$$ --> $$b+c=1.5$$. Sufficient.
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Re: What is the value of b + c ? [#permalink]
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24 Apr 2018, 07:57
Bunuel wrote:
What is the value of b + c ?
(1) ab + cd + ac + bd = 6 --> $$(ab+bd)+(cd+ac)=6$$ --> $$b(a+d)+c(a+d)=6$$ --> $$(a+d)(b+c)=6$$ --> if $$a+d=1$$, then $$b+c=6$$ but if $$a+d=6$$, then $$b+c=1$$. Not sufficient.
(2) a + d = 4. Nothing about $$b$$ and $$c$$. Not sufficient.
(1)+(2) From (1) we have that $$(a+d)(b+c)=6$$ and from (2) we have that $$a + d = 4$$, thus $$4(b+c)=6$$ --> $$b+c=1.5$$. Sufficient.
pushpitkc hello
can you help me please sos cant understand the logic of Bunuels solution...
how from this $$b(a+d)+c(a+d)=6$$ he gets this $$(a+d)(b+c)=6$$
Alsi $$a+d=1$$ how can a+d equal to 1 why a = 0.5 and d = 0.5 ?
and he says if $$b+c=6$$ ... but first statement says that whole expression is 6 ----> ab + cd + ac + bd = 6
and from combing two statements how can $$b+c=1.5$$. why decimal and not integers and why 1.5
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Re: What is the value of b + c ? [#permalink]
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24 Apr 2018, 08:21
1
dave13 wrote:
Bunuel wrote:
What is the value of b + c ?
(1) ab + cd + ac + bd = 6 --> $$(ab+bd)+(cd+ac)=6$$ --> $$b(a+d)+c(a+d)=6$$ --> $$(a+d)(b+c)=6$$ --> if $$a+d=1$$, then $$b+c=6$$ but if $$a+d=6$$, then $$b+c=1$$. Not sufficient.
(2) a + d = 4. Nothing about $$b$$ and $$c$$. Not sufficient.
(1)+(2) From (1) we have that $$(a+d)(b+c)=6$$ and from (2) we have that $$a + d = 4$$, thus $$4(b+c)=6$$ --> $$b+c=1.5$$. Sufficient.
pushpitkc hello
can you help me please sos cant understand the logic of Bunuels solution...
how from this $$b(a+d)+c(a+d)=6$$ he gets this $$(a+d)(b+c)=6$$
Alsi $$a+d=1$$ how can a+d equal to 1 why a = 0.5 and d = 0.5 ?
and he says if $$b+c=6$$ ... but first statement says that whole expression is 6 ----> ab + cd + ac + bd = 6
and from combing two statements how can $$b+c=1.5$$. why decimal and not integers and why 1.5
Hey dave13
To begin with, $$b(a+d)+c(a+d)$$ can also be written as $$(b+c)(a+d)$$
because if you take (a+d) as common, you will get the expression (b+c)
Whenever you have trouble with such expression - put some random values for a,b,c, and d
If a=1,b=2,c=3, and d=4
The right-hand side $$b(a+d)+c(a+d)$$ is $$2(1+4) + 3(1+4) = 2*5 + 3*5 = 25$$
Similarly,the left hand side $$(b+c)(a+d)$$ is $$(2+3)(1+4) = 5*5 = 25$$ and we can prove the same
Coming to the second part of your question, in Bunuel's solution it has been given
If $$a+d=1$$ then $$b+c=6$$ since in statement 1 it is written that $$(a+d)(b+c) = 6$$
The reason it is not sufficient is there is a second possibility when $$a+d=6$$ and $$b+c=1$$
So, (b+c) can have two values - 1 or 6
Hope this helps clear your confusion!
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Re: What is the value of b + c ? [#permalink]
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05 Jul 2018, 11:31
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What is the value of b + c ?
(1) ab + cd + ac + bd = 6
(2) a + d = 4
Target question: What is the value of b + c ?
Statement 1: ab + cd + ac + bd = 6
Rearrange terms: ab + ac + bd + cd = 6
Factor the a out of the first two terms to get: a(b + c) + bd + cd = 6
Factor the d out of the last two terms to get: a(b + c) + d(b + c) = 6
Rewrite as: (a + d)(b + c) = 6
There are infinitely many values of a, b, c and d that satisfy the equation (a + d)(b + c) = 6. Here are two:
Case a: a + d = 1 and b + c = 6. In this case, the answer to the target question is b + c = 6
Case b: a + d = 2 and b + c = 3. In this case, the answer to the target question is b + c = 3
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: a + d = 4
Since we're given NO INFORMATION about b and c, we cannot answer the target question with certainty.
So, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
Statement 1 tells us that (a + d)(b + c) = 6
Statement 2 tells us that a + d = 4
Take the first equation and replace a + d with 4
We get: (4)(b + c) = 6
So, is MUST be the case that b + c = 1.5
Since we can answer the target question with certainty, the combined statements are SUFFICIENT
Cheers,
Brent
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Re: What is the value of b + c ? &nbs [#permalink] 05 Jul 2018, 11:31
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"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.8080671950640463,
"lm_q2_score": 0.6187804267137442,
"lm_q1q2_score": 0.5000161637751089
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
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# What is the value of b + c ?
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# What is the value of b + c ?
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Joined: 02 Dec 2012
Posts: 178
What is the value of b + c ? [#permalink]
### Show Tags
06 Dec 2012, 05:04
1
7
00:00
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85% (00:53) correct 15% (00:50) wrong based on 721 sessions
### HideShow timer Statistics
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Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://solvedlib.com/def-count,241318
|
1 answer
# Def count_overlapping_disks(disks): Right on the heels of the previous Manhattan skyline problem, another classic problem of...
###### Question:
def count_overlapping_disks(disks):
Right on the heels of the previous Manhattan skyline problem, another classic problem of similar spirit that is here best solved with a sweepline algorithm. Given a list of disks on the two-dimensional plane as tuples (x, y, r) so that (x, y) is the center point and r is the radius of that disk, count how many pairs of disks intersect each other in that their areas, including the edge, have at least one point in common. To test whether two disks (x1, y1, r1) and (x2, y2, r2) intersect, use the Pythagorean formula (x2-x1)**2 + (y2-y1)**2 <= (r1+r2)**2. (Note again how this precise formula uses only integer arithmetic whenever all individual components are integers. And no square roots or some other nasty irrational numbers.)
For this problem, crudely looping through all possible pairs of disks would be horrendously inefficient as the list grows larger. However, a sweepline algorithm can solve this problem by looking at a far fewer pairs of disks. Again, sweep through the space from left to right for all relevant x-coordinate values and maintain the set of active disks at the moment. Each individual disk (x, y, r) enters the active set when the sweep line reaches the x-coordinate x-r, and leaves the active set when the sweep line reaches x+r. When a disk enters the active set, check for an intersection between that disk and only the disks presently in the active set.
disks Expected result [(0, 0, 3), (6, 0, 3), (6, 6, 3), (0, 6, 3)] 4 [(4, -1, 3), (-3, 3, 2), (-3, 4, 2), (3, 1, 4)] 2 [(-10, 6, 2), (6, -4, 5), (6, 3, 5), (-9, -8, 1), (1, -5, 3)] 2 [(x, x, x // 2) for x in range(2, 101)] 2563
## Answers
#### Similar Solved Questions
5 answers
##### VibuttDueaLuInPGEVPerendonTercnt Ycar , 1,316,0"6 malc 919,I20 famalc students were cnrollad unjcrgroduatcs RecelvIna ald wete 6060 0( thc malc tudente 67.596 ol utc (crnolc studenu thotc rccelin) Jid, 41.59 of Uv males Icdcnal 51,14 = Icmalct ga: Icjeral ald, Chaoet Audent nde [aril ; Hule trcc dhoram ) nmogabm sccctino udcnt Irom the foloring Cany Yolt Intetucdlcte comautatont catt - drriny Dnone Round thr nnpanuxdt UccimaldleotPer: 0 / RPen 1ol ]trma tldent without 04P(fomala wthoul a
Vibutt DueaLuIn PGEVP erendon Tercnt Ycar , 1,316,0"6 malc 919,I20 famalc students were cnrollad unjcrgroduatcs RecelvIna ald wete 6060 0( thc malc tudente 67.596 ol utc (crnolc studenu thotc rccelin) Jid, 41.59 of Uv males Icdcnal 51,14 = Icmalct ga: Icjeral ald, Chaoet Audent nde [aril ; Hul...
1 answer
##### Carolina Stoneware Company manufactures pottery in two production departments, P1 and P2. The production departments receive...
Carolina Stoneware Company manufactures pottery in two production departments, P1 and P2. The production departments receive services from four support departments, S1, S2, S3 and S4, which also provide some services to each other. The costs of operating the support departments for last year are as ...
1 answer
##### Match the equations with the graphs labeled I-VI and give reasons for your answers. Determine which families of grid curves have $u$ constant and which have $v$ constant. $x = (1 - u)(3 + \cos v) \cos 4 \pi u$, $y = (1 - u)(3 + \cos v) \sin 4 \pi u$, $z = 3u + (1 - u) \sin v$
Match the equations with the graphs labeled I-VI and give reasons for your answers. Determine which families of grid curves have $u$ constant and which have $v$ constant. $x = (1 - u)(3 + \cos v) \cos 4 \pi u$, $y = (1 - u)(3 + \cos v) \sin 4 \pi u$, $z = 3u + (1 - u) \sin v$...
1 answer
5 answers
##### Donna is interested in checking whether there is any differencebetween the proportions of male and female teenagers who useinstant messages (IM) on the Internet every week. 207 out of 300randomly selected teenage girls said they use IM on the internetevery week, while 266 out of 350 randomly selected teenage boyssaid that they use IM on the internet every week. Formulate thenull and alternative hypothesis and test it using significancelevel 0.02.
Donna is interested in checking whether there is any difference between the proportions of male and female teenagers who use instant messages (IM) on the Internet every week. 207 out of 300 randomly selected teenage girls said they use IM on the internet every week, while 266 out of 350 randomly sel...
-- 0.025815--
| 2023-02-05T13:46:27 |
{
"domain": "solvedlib.com",
"url": "https://solvedlib.com/def-count,241318",
"openwebmath_score": 0.3681267201900482,
"openwebmath_perplexity": 5314.65440401674,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.7634837743174789,
"lm_q2_score": 0.6548947425132315,
"lm_q1q2_score": 0.5000015097946755
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"1 answer
# Def count_overlapping_disks(disks): Right on the heels of the previous Manhattan skyline problem, another classic problem of...
###### Question:
def count_overlapping_disks(disks):
Right on the heels of the previous Manhattan skyline problem, another classic problem of similar spirit that is here best solved with a sweepline algorithm. Given a list of disks on the two-dimensional plane as tuples (x, y, r) so that (x, y) is the center point and r is the radius of that disk, count how many pairs of disks intersect each other in that their areas, including the edge, have at least one point in common. To test whether two disks (x1, y1, r1) and (x2, y2, r2) intersect, use the Pythagorean formula (x2-x1)**2 + (y2-y1)**2 <= (r1+r2)**2. (Note again how this precise formula uses only integer arithmetic whenever all individual components are integers. And no square roots or some other nasty irrational numbers.)
For this problem, crudely looping through all possible pairs of disks"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"1 answer
# Def count_overlapping_disks(disks): Right on the heels of the previous Manhattan skyline problem, another classic problem of...
###### Question:
def count_overlapping_disks(disks):
Right on the heels of the previous Manhattan skyline problem, another classic problem of similar spirit that is here best solved with a sweepline algorithm. Given a list of disks on the two-dimensional plane as tuples (x, y, r) so that (x, y) is the center point and r is the radius of that disk, count how many pairs of disks intersect each other in that their areas, including the edge, have at least one point in common. To test whether two disks (x1, y1, r1) and (x2, y2, r2) intersect, use the Pythagorean formula (x2-x1)**2 + (y2-y1)**2 <= (r1+r2)**2. (Note again how this precise formula uses only integer arithmetic whenever all individual components are integers. And no square roots or some other nasty irrational numbers.)
For this problem, crudely looping through all possible pairs of disks"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://www.tex4tum.de/demo.html
|
# Demo of Interactive Features
##### Definition
This page is a showcase of the features that TeX4TUM provides and demonstrates how learning materials could be made interactive, fast accessible, and neat.
Click on the heading to unfold the definition box.
## Interactive Features
### Content Categories
Read only the content you really need. Use the options in the top right corner to change the visibility of the following content:
Using Liquid Tags:
##### Definition
The square root is the math function $\sqrt{\cdot}$.
##### Example
Example $\sqrt{ x^4 } = x^2$
##### Explanation
This is an explanation.
### Interactive Equations
For a low-pass filter, the Cut-Off Frequency is
$f_c = \frac{1}{2\pi R C}$
with the resistance $R$ and capacity $C$
Click on the equation to expand the legend. For resistance $R$ = 10kΩ and capacity $C$ = 100nF the Cut-Off Frequency is $f_c$ = 159 Hz. Click on the values of R and C in the text to change them!
### Interactive Diagrams
Play with diagrams for better understanding. Click and drag the black ray with the mouse or change any value in the diagram.
Find an answer blazingly fast. The fuzzy search in the top bar displays results immediately without slow sever communication. Just hit tab to focus the search, then type e.g. “did” to search for “Diode”.
## Basic Fomartting
### Tables
Tables are easily generated.
Feature Works
Tables yes
MOSI Master Out, Slave In
MISO Master In, Slave Out
### Abreviations
Furthermore, abbreviations such as USB, BIOS, SVG, or JPEG do not need explanations anymore. If you do not know it just move the mouse over it.
### Tab Boxes
You can use boxes with tabs for content that exists in similiar variations.
This should by displayed in tab 1
tabs are simply created by the headers
and this is tab 3. Markdown elements and tex $\sqrt{3}$ are supported.
Also content after the tabbox is displayed normally.
## ToDo
• Full responsive design
• consistent JS framework for interactive content
• More content
## Feature Tests
### Content Categories
Using Liquid Tags:
##### Definition
The square root is the math function $\sqrt{\cdot}$.
##### Example
Example $\sqrt{ x^4 } = x^2$
##### Explanation
$x^4 = x^{2+2} = x^2 \cdot x^2$
where $x$ is an arbitrary number
Using Own Parser:
Definition: The square root is the math function
##### Example
$\sqrt{ x^4 } = x^2$
##### Explanation
The answer is $x^2$ because $x^4 = x^{2+2} = x^2 \cdot x^2$
Legend: where $x$ is an arbitrary number
| 2020-05-27T12:10:42 |
{
"domain": "tex4tum.de",
"url": "https://www.tex4tum.de/demo.html",
"openwebmath_score": 0.4964304268360138,
"openwebmath_perplexity": 7414.958604277718,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837743174789,
"lm_q2_score": 0.6548947425132315,
"lm_q1q2_score": 0.5000015097946755
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Demo of Interactive Features
##### Definition
This page is a showcase of the features that TeX4TUM provides and demonstrates how learning materials could be made interactive, fast accessible, and neat.
Click on the heading to unfold the definition box.
## Interactive Features
### Content Categories
Read only the content you really need. Use the options in the top right corner to change the visibility of the following content:
Using Liquid Tags:
##### Definition
The square root is the math function $\sqrt{\cdot}$.
##### Example
Example $\sqrt{ x^4 } = x^2$
##### Explanation
This is an explanation.
### Interactive Equations
For a low-pass filter, the Cut-Off Frequency is
$f_c = \frac{1}{2\pi R C}$
with the resistance $R$ and capacity $C$
Click on the equation to expand the legend. For resistance $R$ = 10kΩ and capacity $C$ = 100nF the Cut-Off Frequency is $f_c$ = 159 Hz. Click on the values of R and C in the text to change them!
### Interactive Diagrams
Play with d"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Demo of Interactive Features
##### Definition
This page is a showcase of the features that TeX4TUM provides and demonstrates how learning materials could be made interactive, fast accessible, and neat.
Click on the heading to unfold the definition box.
## Interactive Features
### Content Categories
Read only the content you really need. Use the options in the top right corner to change the visibility of the following content:
Using Liquid Tags:
##### Definition
The square root is the math function $\sqrt{\cdot}$.
##### Example
Example $\sqrt{ x^4 } = x^2$
##### Explanation
This is an explanation.
### Interactive Equations
For a low-pass filter, the Cut-Off Frequency is
$f_c = \frac{1}{2\pi R C}$
with the resistance $R$ and capacity $C$
Click on the equation to expand the legend. For resistance $R$ = 10kΩ and capacity $C$ = 100nF the Cut-Off Frequency is $f_c$ = 159 Hz. Click on the values of R and C in the text to change them!
### Interactive Diagrams
Play with d"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://cstheory.stackexchange.com/tags/finite-model-theory/hot?filter=all
|
# Tag Info
11
Here is one possibility, but other people might use different words. I will use first-order logic as a running example. Language The language is a collection of expressions, which are syntactic entities, i.e., finite configurations without any a priori meaning. A language is described by the grammar, which determines which finite configurations are valid ...
8
There are recent exciting results concerning the search for a logic capturing PTIME. The famous example by Cai, Fürer and Immerman showing that LFP+C does not capture PTIME was based on a seemingly artificial class of graphs, though. Of course, it was constructed for the particular task of demonstrating the restrictions of LFP+C. Only recently it was shown ...
8
You can express that $s$ is connected to $t\ne s$ in $G=(V,E)$ by the $\exists\mathrm{MSO}_2$ formula “there exists $E'\subseteq E$ such that in the graph $(V,E')$, $s$ and $t$ have degree $1$, and all other vertices have degree $0$ or $2$.” Note that the formula after the initial $\exists E'$ quantifier is first-order. A graph of degree $\le2$ is a ...
7
Parity cannot be expressed in MSOL (see for instance http://www.cs.technion.ac.il/~janos/COURSES/236331-15/Lec-1.pdf), but connectedness Yes. Using instead $C_2$MSOL, one can express the existence of an eulerian cycle by using the equivalent characterisation : connected and every vertex has degree even.
6
There is a famous example of Cai, Fürer and Immerman, which shows that the $\mathcal{C}_{\infty\omega}^k$-hierarchy is strict and in particular that $\mathcal{C}_{\infty\omega}^\omega$ cannot express every query on finite structures. The paper is quite famous because it disproved a conjecture that IFP+C captures PTIME. Your proof that $\mathcal{L}_{\infty\... 6 The main conferences where automata are among the main topics are ICALP, LICS, STACS, CSL, MFCS, FSTTCS. If you feel your paper is not strong enough for these conferences (which accept about a quarter of the papers that are sent each year), you can send to conferences which are a little less exigeant. The ICALP submission deadline is soon (in a week), ... 6 In fact, the circuit depends on the input structure, not only on the input structure size. We take a tree-decomposition of the graph with additional colours and turn it into a convolution tree. The evaluation of the formula on this tree is reduced to computing the value of the convolution tree. To compute the value of the tree, it is turned into an ... 5 You could start with the survey article by Peter Hinman, Recursion on Abstract Structures, Chapter 11 of the Handbook on Computability Theory (editor E. R. Griffor). If you follow the references there you'll find a wealth of material. 5 This is only a partial answer (to the$PSPACE$characterization), but I don't have the reputation to comment.$PSPACE$has the following (equivalent) descriptive characterizations:$FO[2^{n^{O(1)}}]$, first-order logic with exponentially iterated quantifier blocks.$SO[n^{O(1)}]$, second-order logic with polynomially iterated quantifier blocks.$SO[TC]$, ... 4 I don't know of any natural logic, but the following is in any case a logic for which the combined complexity of the model-checking problem is different for matrix and list encodings. First, we know that for every QBF formula$\psi$there exists a sentence$\varphi_\psi$of FO over the vocabulary$\{P\}$, where$P$is unary, such that$\psi$is true iff$\...
3
Here is another attempt at a more comprehensive answer. Your question already contains the formal definition of FO-rewritability, which at its core says that you can reduce a query answering problem: The problem $D\cup\Sigma\models Q$ is being reduced to a problem $D\models Q_\Sigma$. Several noteworthy things are happening here. The original problem is ...
2
There are Nitpick and Nunchaku that are model finders for higher-order logic. Nunchaku is more recent and can build models for axioms containing higher-order quantification. But, as the problem is generally undecidable, it may not find a (finite) model even if one exists.
2
As mentioned above: question answered by reference to FO(TC) games presented in Finite Model Theory by Ebbinghaus and Flum.
2
First question: A set $M$ is decidable if there is a Turing Machine which halts on all inputs and accepts all inputs $x$ with $x \in M$. We try to encode $\bigwedge_{\phi \in X} \phi$ for arbitrary sets of $\mathsf{FO}[\tau]$-formulars $X$. Since, $\mathcal{P}(X)$ is uncountable there can be no code with finite alphabet. Hence, there can be no Turing ...
2
this is a very old post so you might have already encountered the answer as desired. Since I have been studying FO(LFP) for the past few months. I have some understanding of the answers you require. To answer the requirement of positivity, the need comes from the fact that testing whether the formula captures a monotone operator or not is undecidable both ...
1
As a complement to Janoma's answer above: it's 'very good'--- from the point of view of implementation --- because given a FO-rewritable language, we can use the powerful engines (for evaluating queries directly against a database without dependencies) that are available. That's basically reducing the problem to evaluation of SQL queries.
Only top voted, non community-wiki answers of a minimum length are eligible
| 2021-09-28T11:23:37 |
{
"domain": "stackexchange.com",
"url": "https://cstheory.stackexchange.com/tags/finite-model-theory/hot?filter=all",
"openwebmath_score": 0.7257593870162964,
"openwebmath_perplexity": 442.3890137544725,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837743174788,
"lm_q2_score": 0.6548947425132314,
"lm_q1q2_score": 0.5000015097946754
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Tag Info
11
Here is one possibility, but other people might use different words. I will use first-order logic as a running example. Language The language is a collection of expressions, which are syntactic entities, i.e., finite configurations without any a priori meaning. A language is described by the grammar, which determines which finite configurations are valid ...
8
There are recent exciting results concerning the search for a logic capturing PTIME. The famous example by Cai, Fürer and Immerman showing that LFP+C does not capture PTIME was based on a seemingly artificial class of graphs, though. Of course, it was constructed for the particular task of demonstrating the restrictions of LFP+C. Only recently it was shown ...
8
You can express that $s$ is connected to $t\ne s$ in $G=(V,E)$ by the $\exists\mathrm{MSO}_2$ formula “there exists $E'\subseteq E$ such that in the graph $(V,E')$, $s$ and $t$ have degree $1$, and all other vertices have degree $0$ or $2$.” Note that "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Tag Info
11
Here is one possibility, but other people might use different words. I will use first-order logic as a running example. Language The language is a collection of expressions, which are syntactic entities, i.e., finite configurations without any a priori meaning. A language is described by the grammar, which determines which finite configurations are valid ...
8
There are recent exciting results concerning the search for a logic capturing PTIME. The famous example by Cai, Fürer and Immerman showing that LFP+C does not capture PTIME was based on a seemingly artificial class of graphs, though. Of course, it was constructed for the particular task of demonstrating the restrictions of LFP+C. Only recently it was shown ...
8
You can express that $s$ is connected to $t\ne s$ in $G=(V,E)$ by the $\exists\mathrm{MSO}_2$ formula “there exists $E'\subseteq E$ such that in the graph $(V,E')$, $s$ and $t$ have degree $1$, and all other vertices have degree $0$ or $2$.” Note that "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://electronics.stackexchange.com/questions/76945/current-transformer-behaving-like-voltage-transformer
|
# current transformer behaving like voltage transformer
I wrapped wire around a steel core, and then i put a cable that carries around 10A through the center. This should be a current transformer and should behave like a constant current source. The bigger the load in the secondary the bigger the voltage drop should be (with the current staying constant). And the more the turns of the secondary the less the current should be. But that is not what happened.
As i put bigger resistors in the secondary the current dropped along with the voltage drop. As i wrapped more turns around the core, there was a bigger current and a bigger voltage drop in the secondary.
This behavior is similar to a voltage transformer, isn't it? What is happening?
• What do you think the differences between a "voltage transformer" and a "current transformer" are? Last I checked, there were generally only transformers. – Connor Wolf Jul 25 '13 at 8:33
• Also, where would the additional power going into the load on the secondary come from? If the secondary current stays the same, and the voltage increases, that's also an increase in power. Unless you're putting in a correspondingly larger amount of power, of course the secondary current is going to drop. – Connor Wolf Jul 25 '13 at 8:35
• @Conner the OP says 'should behave like a constant current source' which is IMO correct. The extra power would come from an increased voltage drop over the primary. – Wouter van Ooijen Jul 25 '13 at 9:01
• Based on what i've read all over the internet, in a current transformer current in the primary is not controlled by the secondary load, where in a voltage transformer that is what happens. In a CT, voltage drop in the primary winding (usually only 1, the cable that is passing through the core) is very small, and is stepped up in the secondary. They also say that you should never open circuit a CT, or put a really big resistor because then a big voltage drop would appear in the primary and that would be stepped up based on the turns on the secondary. None of this behavior showed up in my case. – 1p2r3k4t Jul 25 '13 at 9:07
• "Current transformer" and "Voltage transformer" are - in the end - just names. If you wrap wire around a metal core, you get a transformer. If your circuit goes "AC source -> Transformer -> Load" with nothing in there to control things, I would absolutely expect current to change with changing loads. – medivh Jul 25 '13 at 13:26
The differences between a voltage transformer and a current transformer are only in the construction. The theory is the same for both.
The secondary current in a (current) transformer is not constant, regardless of load. The secondary current is only proportional to the primary current with the secondary short-circuited. With the secondary open-circuit, the secondary voltage is proportional to the rate-of-change of the primary current, and might be very large if the primary current changes rapidly.
With a resistive load, the output voltage will depend on both the primary current and it's rate-of-change. Manufacturers of current transformers therefore quote a maximum load resistance (or a maximum secondary voltage) for which the transformer's primary/secondary current ratio will remain in specification.
Here is a Bode plot (on logarithmic axes) of an ideal current transformer. As you would expect, at dc there is no output. Ls represents the secondary inductance, and RL is the resistance in the secondary circuit, ie the sum of the secondary resistance and the load resistance.
If we start with the black line as our transfer function, and our operating frequency is indicated by the blue line, we get the expected 1/N current ratio. If we increase the load resistance RL enough (the red line), our blue line now intersects the transfer function at a lower current ratio. So we require $R_L<2\pi fL_S$ for normal operation.
• The primary winding is usually a very low impedance and therefore treated as a "brute force" constant current source. Faraday's law of ampere-turn balance states that the number of turns in the primary winding times the primary current must equal the number of turns in the secondary winding times the secondary current. since the primary is a constant current source, the secondary becomes a constant current source proportional only to the turns ratio. from link – 1p2r3k4t Jul 25 '13 at 12:35
• I can quote a lot of links and discussions saying the same as above. That is why they also say never to open circuit a CT, as it tries to keep the current constant in the secondary (which will need an infinite voltage since there is infinite resistance) – 1p2r3k4t Jul 25 '13 at 12:37
• That is only true if the secondary is short circuit. With an open-circuit secondary, the secondary voltage is given by $V_S = M\dfrac{\mathrm dI_p}{\mathrm dt}$ - where M is the mutual inductance - that's also Faraday's law. – MikeJ-UK Jul 25 '13 at 12:47
• Isn't the secondary resistance referred to the primary with R2'=TurnsRatio^2*R2 ? Hence a really big resistance and voltage drop on the primary? – 1p2r3k4t Jul 25 '13 at 12:54
• You need to consider the primary inductance too (albeit low). With an open circuit secondary, the primary appears as the primary inductance only (which presents a finite impedance at a finite frequency, and an open-circuit at infinite frequency). With the secondary short-circuit, the primary presents a short-circuit also (ideally). – MikeJ-UK Jul 25 '13 at 13:03
I wrapped wire around a steel core
Unfortunately the steel core you used will act as a shorted turn. You are wrapping your wire around a shorted turn and you expect something sensible to come out - this won't happen.
CTs are just like any other transformer - the iron/steel core should be laminated to reduce induced currents in them. The laminations isolate the induced currents and greatly reduce their influence: -
Note the laminations in the above diagram - the core is made from multiple sheets of silicon steel and each sheet is insulated from each other.
Ferrites are OK because the "iron" is basically dust and surrounding each particle is an insulator - this is lamination technology on a microscopic level.
EDIT I'm editing this to explain why only a finite voltage will be produced by a current transformer. CTs don't behave to some "other" theory - they follow transformer theory and this theory is equipped to deal with CTs. The equivalent circuit is: -
On a normal VT the magnetizing current (see red arrow) is very small because the magnetizing inductance is very large and is typically greater than 10H (generalization). this means it only draws a few milli-amps when the full AC voltage is applied to it.
CTs, on the other hand have a magnetizing inductance that is very small, in the order of micro-henries or a few milli-henries because the primary winding is a single turn. This single turn carries the load current that we wish to measure.
In the middle of the diagram of the transformer equivalent circuit is a "perfect" transformer with a turns ratio of secondary turns divided by primary turns. Thus the voltage across the magnetizing inductance is applied, via the turns ratio to the secondary terminals. On a CT this "input" voltage is a few milli-volts and therefore if the secondary has 300 turns, it will produce 600mV based on an input of 2mV across the magnetizing inductance,
We can neglect leakage inductances to make the "visualization" easier and we end up with this: -
Anything else would not be the laws of physics. You do not get infinite output voltage because there isn't infinite turns ratio. Just because the primary current appears to be going into the "perfect" transformer, look again.... it's actually magnetizing the core and this only produces a few milli volts which is magnified by the turns ratio. It's a transformer just like voltage transformers and has limitations.
• the wire was regular plastic insulated wire you use in electronics projects – 1p2r3k4t Jul 25 '13 at 9:35
• @1p2r3k4t I'm not talking about the wire; I'm talking about the steel core - any transformer has to substantially reduce eddy currents being induced in the core - ferrites or laminations are used. A solid steel core is acting as a shorted turn. – Andy aka Jul 25 '13 at 9:57
• Thanks, i misunderstood what you said. But if you look here link you will see that they also got VT behavior out of their CT – 1p2r3k4t Jul 25 '13 at 10:28
• @1p2r3k4t are they using laminates? – Andy aka Jul 25 '13 at 11:14
• Yes, they used a few flexible foils of mu-metal stacked up to form a laminated core. (edit: The core i used was a toroidal core. Are these laminated inside?) – 1p2r3k4t Jul 25 '13 at 11:21
| 2021-04-13T16:46:59 |
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"domain": "stackexchange.com",
"url": "https://electronics.stackexchange.com/questions/76945/current-transformer-behaving-like-voltage-transformer",
"openwebmath_score": 0.5260104537010193,
"openwebmath_perplexity": 930.6903574466742,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# current transformer behaving like voltage transformer
I wrapped wire around a steel core, and then i put a cable that carries around 10A through the center. This should be a current transformer and should behave like a constant current source. The bigger the load in the secondary the bigger the voltage drop should be (with the current staying constant). And the more the turns of the secondary the less the current should be. But that is not what happened.
As i put bigger resistors in the secondary the current dropped along with the voltage drop. As i wrapped more turns around the core, there was a bigger current and a bigger voltage drop in the secondary.
This behavior is similar to a voltage transformer, isn't it? What is happening?
• What do you think the differences between a "voltage transformer" and a "current transformer" are? Last I checked, there were generally only transformers. – Connor Wolf Jul 25 '13 at 8:33
• Also, where would the additional power going into the load "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Here's an extract from a webpage:
"# current transformer behaving like voltage transformer
I wrapped wire around a steel core, and then i put a cable that carries around 10A through the center. This should be a current transformer and should behave like a constant current source. The bigger the load in the secondary the bigger the voltage drop should be (with the current staying constant). And the more the turns of the secondary the less the current should be. But that is not what happened.
As i put bigger resistors in the secondary the current dropped along with the voltage drop. As i wrapped more turns around the core, there was a bigger current and a bigger voltage drop in the secondary.
This behavior is similar to a voltage transformer, isn't it? What is happening?
• What do you think the differences between a "voltage transformer" and a "current transformer" are? Last I checked, there were generally only transformers. – Connor Wolf Jul 25 '13 at 8:33
• Also, where would the additional power going into the load "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://www.centralvenues.org/srg9dw7/4119cd-fully-connected-layer-tensorflow
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# fully connected layer tensorflow
3. It means all the inputs are connected to the output. Case 2: Number of Parameters of a Fully Connected (FC) Layer connected to a FC Layer. fully_connectedcreates a variable called weights, representing a fully connected weight matrix, which is multiplied by the inputsto produce a Tensorof hidden units. The following are 30 code examples for showing how to use tensorflow.contrib.layers.fully_connected(). The most comfortable set up is a binary classification with only two classes: 0 and 1. Finally, if activation_fn is not None, Many machine learning models are expressible as the composition and stacking of relatively simple layers, and TensorFlow provides both a set of many common layers as a well as easy ways for you to write your own application-specific layers either from scratch or as the composition of existing layers. dtype: The data type expected by the input, as a string (float32, float64, int32...) name: An optional name string for the layer. Many machine learning models are expressible as the composition and stacking of relatively simple layers, and TensorFlow provides both a set of many common layers as a well as easy ways for you to write your own application-specific layers either from scratch or as the composition of existing layers. The classic neural network architecture was found to be inefficient for computer vision tasks. matmul ( layer_1 , weights [ 'h2' ]), biases [ 'b2' ]) # Output fully connected layer with a neuron for each class Deep learning often uses a technique called cross entropy to define the loss. 转载请注明出处。 一、简介： 1、相比于第一个例程，在程序上做了优化，将特定功能以函数进行封装，独立可能修改的变量，使程序架构更清晰。 It may seem that, for example, layer flattening and max pooling donât store any parameters trained in the learning process. Either a shape or placeholder must be provided, otherwise an exception will be raised. with (tf. The fully connected layer (dense layer) is a layer where the input from other layers will be depressed into the vector. They involve a lot of computation as well. The complexity of the network is adding a lot of overhead, but we are rewarded with better accuracy. Dense Layer is also called fully connected layer, which is widely used in deep learning model. tensorflow示例学习--贰 fully_connected_feed.py mnist.py. We will not call the softmax here. created and added the hidden units. For the actual training, let’s start simple and create the network with just one output layer. A dense layer can be defined as: A fully connected neural network consists of a series of fully connected layers. The definition itself takes the input data and connects to the output layer: Notice that this time, we used an activation parameter. It will transform the output into any desired number of classes into the network. For those monotonic features (such as the budget of the movie), we fuse them with non-monotonic features using a lattice structure. placeholder (tf. Convolutional layers can be implemented in TensorFlow using the ... 24 and then add dropout on the fully-connected layer. Keras layers and models are fully compatible with pure-TensorFlow tensors, and as a result, Keras makes a great model definition add-on for TensorFlow, and can even be used alongside other TensorFlow libraries. On the other hand, this will improve the accuracy significantly, to the 94% level. If a normalizer_fn is provided (such as According to our discussions of parameterization cost of fully-connected layers in Section 3.4.3, even an aggressive reduction to one thousand hidden dimensions would require a fully-connected layer characterized by $$10^6 \times 10^3 = 10^9$$ parameters. A receptive field of a neuron is the range of input flowing into the neuron. This allow us to change the inputs (images and labels) to the TensorFlow graph. TensorFlow offers many kinds of layers in its tf.layers package. float32, shape: (-1, img_size_flat), name: "X"); y = tf. Nonetheless, they are performing more complex operations than activation function, so the authors of the module decided to set them up as separate classes. View all O’Reilly videos, Superstream events, and Meet the Expert sessions on your home TV. Fully Connected Layer. For every word, we can have an attention vector generated that captures contextual relationships between words in a sentence. xavier_initializer(...) : Returns an initializer performing "Xavier" initialization for weights. As a result, the network layers become much smaller but increase in depth. Right now, we have a simple neural network that reads the MNIST dataset which consists of a series of images and runs it through a single, fully connected layer with rectified linear activation and uses it to make predictions. This article will explain fundamental concepts of neural network layers and walk through the process of creating several types using TensorFlow. First of all, we need a placeholder to be used in both the training and testing phases to hold the probability of the Dropout. The last fully-connected layer will contain as many neurons as the number of classes to be predicted. In TensorFlow, the softmax and cost function are lumped together into a single function, which you'll call in a different function when computing the cost. This post is a collaboration between O’Reilly and TensorFlow. After this step, we apply max pooling. We again are using the 2D input, but flattening only the output of the second layer. fully_connected creates a variable called weights, representing a fully connected weight matrix, which is multiplied by the inputs to produce a Tensor of hidden units. Therefore, That’s an order of magnitude more than the total number of parameters of all the Conv Layers combined! Remove fully-connected layers in deeper networks. The task is to recognize a digit ranging from 0 to 9 from its handwritten representation. To create the fully connected with "dense" layer, the new shape needs to be [-1, 7 x 7 x 64]. output represents the network predictions and will be defined in the next section when building the network. This easy-to-follow tutorial is broken down into 3 sections: Deep learning has proven its effectiveness in many fields, such as computer vision, natural language processing (NLP), text translation, or speech to text. FCN is a network that does not contain any “Dense” layers (as in traditional CNNs) instead it contains 1x1 convolutions that perform the task of fully connected layers (Dense layers). It means the network will learn specific patterns within the picture and will be able to recognize it everywhere in the picture. fully_connected creates a variable called weights, representing a fully The fourth layer is a fully-connected layer with 84 units. name_scope ("Input"), delegate {// Placeholders for inputs (x) and outputs(y) x = tf. Fixed batch size for layer. Go for it and break the 99% limit. For other types of networks, like RNNs, you may need to look at tf.contrib.rnn or tf.nn. Fully connected layers in a CNN are not to be confused with fully connected neural networks – the classic neural network architecture, in which all neurons connect to all neurons in the next layer. The implementation of tf.contrib.layers.fully_connected uses variable_op_scope to handle the name scope of the variables, the problem is that the name scope is only uniquified if scope is None, that is, if you dont pass a custom name, by default it will be "fully_connected".. Their neurons reuse the same weights, so dropout, which effectively works by freezing some weights during one training iteration, would not work on them. In other words, the dense layer is a fully connected layer, meaning all the neurons in a layer are connected to those in the next layer. The structure of a dense layer look like: Here the activation function is Relu. It runs whatever comes out of the neuron through the activation function, which in this case is ReLU. This is done by instantiating the pre-trained model and adding a fully-connected classifier on top. dtype: The data type expected by the input, as a string (float32, float64, int32...) name: An optional name string for the layer. This example is using the MNIST database A typical convolutional network is a sequence of convolution and pooling pairs, followed by a few fully connected layers. Figure 1: A basic siamese network architecture implementation accepts two input images (left), has identical CNN subnetworks for each input with each subnetwork ending in a fully-connected layer (middle), computes the Euclidean distance between the fully-connected layer outputs, and then passes the distance through a sigmoid activation function to determine similarity (right) (figure … Lec29E tensorflow keras training of fully connected layer, PSEP501 POSTECH SAMSUNG semiconductorE keras sequential layer, relu, tensorflow lite, tensorflow … Therefore, That’s an order of magnitude more than the total number of parameters of all the Conv Layers combined! It can be calculated in the same way for … The size of the output layer corresponds to the number of labels. You can find a large range of types there: fully connected, convolution, pooling, flatten, batch normalization, dropout, and convolution transpose. Try decreasing/increasing the input shape, kernel size or strides to satisfy the condition in step 4. Convolutional neural networks enable deep learning for computer vision.. with (tf. fully-connected layer: Neural network consists of stacks of fully-connected (dense) layers. Max pooling is the most common pooling algorithm, and has proven to be effective in many computer vision tasks. Reshape output of convolution and pooling layers, flattening it to prepare for the fully connected layer. What is a dense neural network? - FULLYCONNECTED (FC) layer: We'll apply fully connected layer without an non-linear activation function. Tensorflow(prior to 2.0) is a build and run type of a library, everything must be preconfigured then “compiled” when a session starts. Tensor of hidden units. it is applied to the hidden units as well. Why not on the convolutional layers? TensorFlow provides a set of tools for building neural network architectures, and then training and serving the models. The pre-trained model is "frozen" and only the weights of the classifier get updated during training. A fully connected layer is defined such that every input unit is connected to every output unit much like the multilayer ... ReLU activation, is added right before the final fully connected layer. The key lesson from this exercise is that you donât need to master statistical techniques or write complex matrix multiplication code to create an AI model. A TensorFlow placeholder will be used if it is supplied, otherwise a new placeholder will be created with the given shape. It is the same for a network. We use a softmax activation function to classify the number on the input image. The encoder block has two sub-layers. tensorflow示例学习--贰 fully_connected_feed.py mnist.py. Imagine you have a math problem, the first thing you do is to read the corresponding chapter to solve the problem. A fully connected layer is a function from ℝ m to ℝ n. Each output dimension depends on each input dimension. All you need to provide is the input and the size of the layer. There is a high chance you will not score very well. This network will take in 4 numbers as an input, and output a single continuous (linear) output. The output layer is a softmax layer with 10 outputs. In the above diagram, the map matrix is converted into the vector such as x1, x2, x3... xn with the help of a This allow us to change the inputs (images and labels) to the TensorFlow graph. trainable: Whether the layer weights will be updated during training. The implementation of tf.contrib.layers.fully_connected uses variable_op_scope to handle the name scope of the variables, the problem is that the name scope is only uniquified if scope is None, that is, if you dont pass a custom name, by default it will be "fully_connected". To take full advantage of the model, we should continue with another layer. We’d lost it when we flattened the digits pictures and fed the resulting data into the dense layer. The tensor variable representing the result of the series of operations. The TensorFlow layers module provides a high-level API that makes it easy to construct a neural network. Our first network isn’t that impressive in regard to accuracy. This will result in 2 neurons in the output layer, which then get passed later to a softmax. For this layer, , and . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. Here are instructions on how to do this. In the above diagram, the map matrix is converted into the vector such as x1, x2, x3... xn with the help of a A typical neural network takes a vector of input and a scalar that contains the labels. Use ReLU in the generator except for the final layer, which will utilize tanh. The first one doesn’t need flattening now because the convolution works with higher dimensions. The structure of dense layer. The encoder block has two sub-layers. Today, we’re going to learn how to add layers to a neural network in TensorFlow. Example: The first fully connected layer of AlexNet is connected to a Conv Layer. It will be autogenerated if it isn't provided. According to our discussions of parameterization cost of fully-connected layers in Section 3.4.3, even an aggressive reduction to one thousand hidden dimensions would require a fully-connected layer characterized by $$10^6 \times 10^3 = 10^9$$ parameters. You should see a slight decrease in performance. The rest of the architecture stays the same. fully-connected layer: Neural network consists of stacks of fully-connected (dense) layers. For the MNIST data set, the next_batch function would just call mnist.train.next_batch. Some minor changes are needed from the previous architecture. placeholder (tf. We will set up Keras using Tensorflow for the back end, and build your first neural network using the Keras Sequential model api, with three Dense (fully connected) layers. Join the O'Reilly online learning platform. To evaluate the performance of the training process, we want to compare the output with the real labels and calculate the accuracy: Now, weâll introduce a simple training process using batches and a fixed number of steps and learning rate. It offers different levels of abstraction, so you can use it for cut-and-dried machine learning processes at a high level or go more in-depth and write the low-level calculations yourself. Get a free trial today and find answers on the fly, or master something new and useful. This is because, a dot product layer has an extreme receptive field. Ensure that you get (1, 1, num_of_filters) as the output dimension from the last convolution block (this will be input to fully connected layer). The most basic type of layer is the fully connected one. Each neuron in a layer receives an input from all the neurons present in the previous layer—thus, they’re densely connected. The most basic neural network architecture in deep learning is the dense neural networks consisting of dense layers (a.k.a. Their neurons reuse the same weights, so dropout, which effectively works by freezing some weights during one training iteration, would not work on them. This algorithm has been proven to work quite well with deep architectures. We’re just at the beginning of an explosion of intelligent software. The structure of a dense layer look like: Here the activation function is Relu. Pooling is the operation that usually decreases the size of the input image. A step-by-step tutorial on how to use TensorFlow to build a multi-layered convolutional network. Figure 1: A basic siamese network architecture implementation accepts two input images (left), has identical CNN subnetworks for each input with each subnetwork ending in a fully-connected layer (middle), computes the Euclidean distance between the fully-connected layer outputs, and then passes the distance through a sigmoid activation function to determine similarity (right) (figure … Example: The first fully connected layer of AlexNet is connected to a Conv Layer. Their neurons reuse the same weights, so dropout, which effectively works by freezing some weights during one training iteration, would not work on them. We also use non-monotonic structures (e.g., fully connected layers) to fuse non-monotonic features (such as length of the movie, season of the premiere) into a few outputs. fully-connected layer: Neural network consists of stacks of fully-connected (dense) layers. The module makes it easy to create a layer in the deep learning model without going into many details. The code for convolution and max pooling follows. This is a short introduction to computer vision — namely, how to build a binary image classifier using only fully-connected layers in TensorFlow/Keras, geared mainly towards new users. Defined in tensorflow/contrib/layers/python/layers/layers.py. The second layer is another convolutional layer, the kernel size is (5,5), the number of filters is 16. In this article, we started by introducing the concepts of deep learning and used TensorFlow to build a multi-layered convolutional network. Below is a ConvNet defined with the Layers library and Estimators API in TensorFlow . The third layer is a fully-connected layer with 120 units. In this layer, all the inputs and outputs are connected to all the neurons in each layer. Notice that for the next connection with the dense layer, the output must be flattened back. Be aware that the variety of choices in libraries like TensorFlow give you requires a lot of responsibility on your side. The classic neural network architecture was found to be inefficient for computer vision tasks. Go for it and break the 99% limit. weights It will transform the output into any desired number of classes into the network. Pictorially, a fully connected layer is represented as follows in Figure 4-1. fully-connected layer: Neural network consists of stacks of fully-connected (dense) layers. Should be unique in a model (do not reuse the same name twice). fully-connected layer: Neural network consists of stacks of fully-connected (dense) layers. One opinion states that a layer must store trained parameters (like weights and biases). Fully Connected (Dense) Layer. Otherwise, if normalizer_fnis A typical neural network is often processed by densely connected layers (also called fully connected layers). The inputsto produce a Tensorof hidden units as well as more sophisticated twists, such as batch_norm,. Several types using TensorFlow from 0 to 9 from its handwritten representation called fully connected layer dense. Created with the data from the high number of parameters of all the inputs ( x and... Means, for Example, we need to do is to use,... Padding set of tools for building neural network that is applied repeatedly, once each! Img_Size_Flat ), name: x '' ) ; y = tf solve problem! The fully connected layer tensorflow and discriminator matrix, which is multiplied by the inputsto a. The dropout and connect it to the TensorFlow backend ( instead of Theano ) which makes coding easier the,! The picture and will represent the underlying truth initialization for weights ) layers ) layers offers many kinds layers! We use a softmax this will result in 2 neurons in each layer that layers are connected. Normalizer_Fnis at the beginning of this section, we can check its performance on the fully-connected layer with size... Dense class multiplied by the tf.train API layers combined however, would greater. Flattened back of Theano ) which makes coding easier activation parameter first thing you do to! Inputs and outputs ( y ) x = tf get updated during training up the layer! Step-By-Step tutorial on how to use some of them to build a convolutional. Convolution convolution operation is an element-wise matrix multiplication operation of service ⢠Privacy policy ⢠Editorial independence of fully-connected dense... Fed the resulting layer is a sequence of convolution and pooling layers, flattening it to the original,. A fully connected feed-forward network range of input and a scalar that contains the.. Therefore, that applying the activation parameter represents the network performance and avoid.. Great support, or master something new and useful work differently from the MNIST data set introducing the of... Outputs ( y ) x = tf what a layer receives an input, and output a single continuous linear! As: defined in tensorflow/contrib/layers/python/layers/layers.py, we need to define the loss function, will! Basic neural network consists of stacks of fully-connected ( dense ) layers float32, shape (. The vector © 2020, O ’ Reilly Media, Inc. all trademarks and trademarks! Softmax layer with 10 outputs your side blocks are will learn specific patterns the. Between O ’ Reilly Media, Inc. all trademarks and registered trademarks appearing on fully connected layer tensorflow are integral! Layer ( dense ) layers which in this layer, which will utilize tanh they work from. Consisting of dense layers ( also called fully connected layer first fully connected (! May check out the related API usage on the fully-connected layer at runtime done instantiating... Model, we need to define the dropout and connect it to the TensorFlow backend ( instead of Theano.... Rule, though params is 400 * 120+120= 48120, delegate { Placeholders... Learning beginners a convolution is like a small neural network in TensorFlow line of code,. Representation on TensorFlow Playground fully-connected layer: we 'll apply fully connected layer the! The deep learning for computer vision a digit ranging from 0 to 9 from its handwritten representation ). During the training phase, so it runs whatever comes out of the output layer Media, Inc. trademarks! And avoid overfitting creating several types using TensorFlow a normalizer_fnis provided ( such the. Reshape output of the previous layer—thus, they are not ideal for as! Representing the result of the previous architecture the difference between the network predictions and actual labels ’..
| 2021-08-04T00:47:10 |
{
"domain": "centralvenues.org",
"url": "https://www.centralvenues.org/srg9dw7/4119cd-fully-connected-layer-tensorflow",
"openwebmath_score": 0.5069034695625305,
"openwebmath_perplexity": 948.5192100810713,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# fully connected layer tensorflow
3. It means all the inputs are connected to the output. Case 2: Number of Parameters of a Fully Connected (FC) Layer connected to a FC Layer. fully_connectedcreates a variable called weights, representing a fully connected weight matrix, which is multiplied by the inputsto produce a Tensorof hidden units. The following are 30 code examples for showing how to use tensorflow.contrib.layers.fully_connected(). The most comfortable set up is a binary classification with only two classes: 0 and 1. Finally, if activation_fn is not None, Many machine learning models are expressible as the composition and stacking of relatively simple layers, and TensorFlow provides both a set of many common layers as a well as easy ways for you to write your own application-specific layers either from scratch or as the composition of existing layers. dtype: The data type expected by the input, as a string (float32, float64, int32...) name: An optional name string for the lay"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"# fully connected layer tensorflow
3. It means all the inputs are connected to the output. Case 2: Number of Parameters of a Fully Connected (FC) Layer connected to a FC Layer. fully_connectedcreates a variable called weights, representing a fully connected weight matrix, which is multiplied by the inputsto produce a Tensorof hidden units. The following are 30 code examples for showing how to use tensorflow.contrib.layers.fully_connected(). The most comfortable set up is a binary classification with only two classes: 0 and 1. Finally, if activation_fn is not None, Many machine learning models are expressible as the composition and stacking of relatively simple layers, and TensorFlow provides both a set of many common layers as a well as easy ways for you to write your own application-specific layers either from scratch or as the composition of existing layers. dtype: The data type expected by the input, as a string (float32, float64, int32...) name: An optional name string for the lay"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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# boundary line definition in mathematics
You'll note that some of the state boundaries are defined by bodies of water, like how Wisconsin is bordered by Lake Michigan and Lake Superior. A line or border around the outside of a shape. How to use bound in a sentence. Find out what you can do. Boundary Line Agreement. Every inequality has a boundary line, which is the equation produced by changing the inequality relation to an equals sign. In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions.. If M is a manifold with boundary of dimension n , then Int M is a manifold (without boundary) of dimension n and ∂ M is a manifold (without boundary) of dimension n − 1 . 1 2. Append content without editing the whole page source. Meaning of boundary line. Notations used for boundary of a set S include bd(S), fr(S), and $${\displaystyle \partial S}$$. boundary line, border, borderline, delimitation, mete(noun), The numerical value of boundary line in Chaldean Numerology is: 6, The numerical value of boundary line in Pythagorean Numerology is: 5. The Boundary line defines the space or area. Notify administrators if there is objectionable content in this page. across/ along/ on/ over a/ the border/ boundary/ frontier; at the boundary/ frontier; the border/ boundary/ frontier with a place If the boundary line is solid, then the linear inequality must be either ≥ or ≤. Wikidot.com Terms of Service - what you can, what you should not etc. The solution is the region where the shading overlaps. Clifford is enjoying life north of the border. Click here to edit contents of this page. There is a boundary line for each and every shape. https://www.definitions.net/definition/boundary+line. Other s… In particular, a set is open exactly when it does not contain its boundary. Synonyms. Many properties are rectangular, but not all are. STANDS4 LLC, 2020. Introduction to boundary line math definition: The boundary line is defined as the line or border around outside of a shape. Also answering questio . View/set parent page (used for creating breadcrumbs and structured layout). On one side of the line are the points with $$2x+3y>6$$ and on the other side of the line are the points with $$2x+3y<6$$. Shade in the side of the boundary line where the inequality is true. Some authors (for example Willard, in General Topology) use the term frontier instead of boundary in an attempt to avoid confusion with a different definition used in algebraic topology and the theory of manifolds. The closure of $A$ is: Hence we see that the boundary of $A$ is as expected: For another example, consider the set $B = [0, 1) \cup (2, 3) \subset \mathbb{R}$. the dataset has a smallest and largest value. ... Thesaurus for boundary from the Collins English Thesaurus. [Added:] The definition you gave "Open set with none, some, or all of its boundary points" is seldom used. For most people who live along the northern border of Portugal, crossing the boundary line is now commonplace, there is a strong cultural proximity, a single universe divided by a border. Answer. ]a hit … The boundary line is dashed for > and < and solid for ≥ and ≤. One side of the boundary line contains all solutions to the inequality. Write the inequality shown by the graph. One side of the boundary will have points that satisfy the inequality, and the other side will have points that falsify it. Shade in the side of that boundary line where the inequality is true. We're doing our best to make sure our content is useful, accurate and safe.If by any chance you spot an inappropriate comment while navigating through our website please use this form to let us know, and we'll take care of it shortly. noun Mathematics. Utah Code section 57-1-45(1): If properly executed and acknowledged as required under this chapter, an agreementbetween property owners designating the boundary line between their properties, when recorded in the office of the recorder of the county in which the property is located, shall act as a quitclaim deed and [ Cricket. Thanks for your vote! Watch headings for an "edit" link when available. These two definitions, however, are completely equivalent. something that indicates the farthest limit, such as of an area ... the dividing line between political or geographic regions. One of the simplest but most important concepts in real property law is the concept of boundary. This means that if L is the linear differential operator, then . Get instant definitions for any word that hits you anywhere on the web! No matter the shape of your property, the boundary line of your property will create a geometric shape. Definition. It defines the space or area. We're doing our best to make sure our content is useful, accurate and safe.If by any chance you spot an inappropriate image within your search results please use this form to let us know, and we'll take care of it shortly. The set of all boundary points of is called the Boundary of and is denoted. If you look at a political map of the United States, you will see boundary lines delineating each of the states. How to say boundary line in sign language? See pages that link to and include this page. It defines the space or area. Equivalently, $x \in \partial A$ if every $U \in \tau$ with $x \in U$ intersects $A$ and $A^c = X \setminus A$ nontrivially. Graph the boundary line. 30 synonyms of boundary from the Merriam-Webster Thesaurus, plus 40 related words, definitions, and antonyms. Check out how this page has evolved in the past. "boundary line." New from Collins Quick word challenge. Check by choosing a test point. If you were to look down at your property from a bird's eye view, you would see a geometric shape. The Boundary of a Set in a Topological Space Definition: Let be a topological space and. Despite widespread acceptance of the meaning of the terms boundary and frontier, they have sometimes been used to refer to other sets. Each class thus has an upper and a lower class boundary. The boundary line indicating an edge of something. The closure of $A$ is: Hence we see that the boundary of $B$ is: For a third example, consider the set $X = \mathbb{R}^2$ with the the usual topology $\tau$ containing open disks with positive radii. See more. The linear inequality divides the coordinate plane into two halves by a boundary line (the line that corresponds to the function). To give an example which is not a region under this definition is rather easy: just consider a set with only a single point on the complex plane. Definitions.net. An alternative to this approach is to take closed sets as complements of open sets. $x \in \bar{A} \setminus \mathrm{int} (A)$, $\partial A = \bar{A} \setminus \mathrm{int} (A)$, $\overline{X \setminus A} = X \setminus \mathrm{int}(A)$, $\overline{X \setminus A} \subseteq X \setminus \mathrm{int}(A)$, $\overline{X \setminus A} \supseteq X \setminus \mathrm{int}(A)$, $\partial A = \overline{A} \cap \overline{X \setminus A}$, $\partial A = \overline{A} \setminus \mathrm{int}(A)$, $B = [0, 1) \cup (2, 3) \subset \mathbb{R}$, $A = [0, 1) \times [0, 1) \subseteq \mathbb{R}^2$, Creative Commons Attribution-ShareAlike 3.0 License, So there does NOT exist an open neighbourhood of, Comparing the two above expressions yields. Another equivalent definition for the boundary of $A$ is the set of all points $x \in X$ such that every open neighbourhood of $x$ contains at least one point of $A$ and at least one point of $X \setminus A$. On the same grid, graph the second inequality. View wiki source for this page without editing. Line of Control a 450-mile line that is supposed to indicate the boundary between the part of Kashmir controlled by India and the part controlled by Pakistan Mason and Dixon's line the boundary between Maryland and Pennsylvania; symbolic dividing line between North … The boundary points can be characterized as those points which land on the boundary hyperplane (x n = 0) of R n + under some coordinate chart. A boundaryis either a natural object, like a river or lake, or an imaginary line that defines the perimeter of a parcel of land. the collection of all points of a given set having the property that every neighborhood of each point contains points in the set and in the complement of the set. Boundary is a border that encloses a space or an area...Complete information about the boundary, definition of an boundary, examples of an boundary, step by step solution of problems involving boundary. Consider the topological space $(\mathbb{R}, \tau)$ where $\tau$ is the usual topology on $\mathbb{R}$ of open intervals and consider the set $A = [0, 1) \subset \mathbb{R}$. General Wikidot.com documentation and help section. 1. an often imaginary line separating one thing from another. For example, the term frontier has been used to describe the residue of S, namely S \ S (the set of boundary points not in S). In math, we use the term perimeter to indicate the distance around the outer edge of a shape. Boundary Boundary A line or border around the outside of a shape. | Meaning, pronunciation, translations and examples Boundary definition, something that indicates bounds or limits; a limiting or bounding line. In topology and mathematics in general, the boundary of a subset S of a topological space X is the set of points which can be approached both from S and from the outside of S. More precisely, it is the set of points in the closure of S not belonging to the interior of S. An element of the boundary of S is called a boundary point of S. The term boundary operation refers to finding or taking the boundary of a set. I.e., $x \in \partial A$ if and only if for every open neighbourhood $U$ of $x$ we have that $A \cap U \neq \emptyset$ and $(X \setminus A) \cap U \neq \emptyset$. The limits of an area can be determined by the boundary line. Illustrated definition of Line: In common language it is a long thin mark made by a pen, pencil, etc. View and manage file attachments for this page. the boundary between two towns. The boundary line lies instantly inside the boundary. If you want to discuss contents of this page - this is the easiest way to do it. To find where the Boundary Line is for the contiguous U.S., use this link to 46 CFR Part 7. It helps you to determine what's insid Definition of Boundary - Math Definitions - Letter B Mathematics Also called frontier. Let $A = [0, 1) \times [0, 1) \subseteq \mathbb{R}^2$. Felix Hausdorff named the intersection of S with its boundary the border of S (the term boundary is used to refer to this set in Metric Spaces by E. T. Copson). Let's look at a quick example. Definition of Boundary A boundary is a line or border that runs around the edge of a shape or region of the plane. What does boundary line mean? Web. This line is often found on charts of appropriate scale.) Conquering any difficulty always gives one a secret joy, for it means pushing back a boundary-line and adding to one's liberty. Boundary: a real or imaginary point beyond which a … 2 Dec. 2020. the boundary between two towns. The line $$2x+3y=6$$ is the boundary line. If the boundary line is dotted, then the linear inequality must be either > or <> Information and translations of boundary line in the most comprehensive dictionary definitions resource on the web. When you did boundary training with your dog, you walked around the edge of your property line. The boundary line shown is $$2x+3y=6$$. When we have different classes of data, there is always an upper and a lower class limit for it i.e. Class boundary is the midpoint of the upper class limit of one class and the lower class limit of the subsequent class. Find another word for boundary. Definition of boundary line in the Definitions.net dictionary. Boundary can also be a physical line between two places, for example between property belonging to two different people, marked by a fence or wall: the boundary fence/ wall between the properties; Patterns. 1. an often imaginary line separating one thing from another. A linear inequality divides a plane into two parts. Boundary line for contour. The boundary line is drawn as a dashed line (if or $>$ is used) or a solid line (if $\leq$ or $\geq$ is used). Bound definition is - fastened by or as if by a band : confined. any of a series of problems occurring in the solution of a differential equation with boundary conditions. Then $A$ can be depicted as illustrated: Then the boundary of $A$, $\partial A$ is therefore the set of points illustrated in the image below: The Boundary of a Set in a Topological Space, \begin{align} \quad U \cap (X \setminus A) \neq \emptyset \end{align}, \begin{align} \overline{X \setminus A} = X \setminus \mathrm{int}(A) \quad \blacksquare \end{align}, \begin{align} \quad \partial A = \overline{A} \cap (X \setminus \mathrm{int}(A)) \end{align}, \begin{align} \quad \partial A = \overline{A} \cap \overline{X \setminus A} \quad \blacksquare \end{align}, \begin{align} \quad \partial A = \overline{A} \cap \overline{X \setminus A} \end{align}, \begin{align} \quad \partial (X \setminus A) = \overline{X \setminus A} \cap \overline{X \setminus (X \setminus A)} = \overline{X \setminus A} \cap \overline{A} \end{align}, \begin{align} \quad \bar{A} = [0, 1] \end{align}, \begin{align} \quad \mathrm{int} (A) = (0, 1) \end{align}, \begin{align} \quad \partial A = \bar{A} \setminus \mathrm{int} (A) = [0, 1] \setminus (0, 1) = \{0, 1 \} \end{align}, \begin{align} \quad \bar{B} = [0, 1] \cup [2, 3] \end{align}, \begin{align} \quad \mathrm{int} (B) = (0, 1) \cup (2, 3) \end{align}, \begin{align} \quad \partial B = \bar{B} \setminus \mathrm{int} (B) = [[0, 1] \cup [2, 3]] \setminus [(0, 1) \cup (2, 3)] = \{ 0, 1, 2, 3 \} \end{align}, Unless otherwise stated, the content of this page is licensed under. Something does not work as expected? Quiz Review. Learn more about contourf, boundary A point is said to be a Boundary Point of if is in the closure of but not in the interior of, i.e.,. Change the name (also URL address, possibly the category) of the page. We truly appreciate your support. Boundary definition: The boundary of an area of land is an imaginary line that separates it from other areas. Gulf of Mexico exception: 46 CFR Part 7 delineates that the Boundary Line in the Gulf of Mexico is along the 12-mile line which marks the seaward limits of the Contiguous Zone. Graph the boundary line. Click here to toggle editing of individual sections of the page (if possible).
Posted in 게시판.
| 2021-05-16T08:35:19 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# boundary line definition in mathematics
You'll note that some of the state boundaries are defined by bodies of water, like how Wisconsin is bordered by Lake Michigan and Lake Superior. A line or border around the outside of a shape. How to use bound in a sentence. Find out what you can do. Boundary Line Agreement. Every inequality has a boundary line, which is the equation produced by changing the inequality relation to an equals sign. In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions.. If M is a manifold with boundary of dimension n , then Int M is a manifold (without boundary) of dimension n and ∂ M is a manifold (without boundary) of dimension n − 1 . 1 2. Append content without editing the whole page source. Meaning of boundary line. Notations used for boundary of a set S include bd(S), fr(S), and $${\displaystyle \partial S}$$. boundary line, bo"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Here's an extract from a webpage:
"# boundary line definition in mathematics
You'll note that some of the state boundaries are defined by bodies of water, like how Wisconsin is bordered by Lake Michigan and Lake Superior. A line or border around the outside of a shape. How to use bound in a sentence. Find out what you can do. Boundary Line Agreement. Every inequality has a boundary line, which is the equation produced by changing the inequality relation to an equals sign. In mathematics, a Green's function is the impulse response of an inhomogeneous linear differential operator defined on a domain with specified initial conditions or boundary conditions.. If M is a manifold with boundary of dimension n , then Int M is a manifold (without boundary) of dimension n and ∂ M is a manifold (without boundary) of dimension n − 1 . 1 2. Append content without editing the whole page source. Meaning of boundary line. Notations used for boundary of a set S include bd(S), fr(S), and $${\displaystyle \partial S}$$. boundary line, bo"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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http://matheducators.stackexchange.com/questions/2165/references-for-high-school-mathematics-from-an-advanced-point-of-view
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# References for “high-school mathematics from an advanced point of view”
What are some good references for high-school (or even middle-school) mathematics, written from an advanced point of view, especially texts written for prospective teachers?
Some references were given in a comment for an earlier question, but I cannot find that one now ...
-
I sympathize with this question, because unfortunately a lot of valuable content on this site is getting hidden in the comments. – Chris Cunningham May 5 at 15:36
– Benjamin Dickman May 5 at 17:03
Check this and this. – metacompactness May 25 at 21:58
Right now the best-known book of this sort is "Mathematics for High School Teachers -- An Advanced Perspective" by Zalman Usiskin. (I say "right now" because I have grandiose plans of writing such a textbook myself, but not until after I get tenure, i.e. not for at least 3 years.)
-
| 2014-07-22T23:52:58 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# References for “high-school mathematics from an advanced point of view”
What are some good references for high-school (or even middle-school) mathematics, written from an advanced point of view, especially texts written for prospective teachers?
Some references were given in a comment for an earlier question, but I cannot find that one now ...
-
I sympathize with this question, because unfortunately a lot of valuable content on this site is getting hidden in the comments. – Chris Cunningham May 5 at 15:36
– Benjamin Dickman May 5 at 17:03
Check this and this. – metacompactness May 25 at 21:58
Right now the best-known book of this sort is "Mathematics for High School Teachers -- An Advanced Perspective" by Zalman Usiskin. (I say "right now" because I have grandiose plans of writing such a textbook myself, but not until after I get tenure, i.e. not for at least 3 years.)
-"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# References for “high-school mathematics from an advanced point of view”
What are some good references for high-school (or even middle-school) mathematics, written from an advanced point of view, especially texts written for prospective teachers?
Some references were given in a comment for an earlier question, but I cannot find that one now ...
-
I sympathize with this question, because unfortunately a lot of valuable content on this site is getting hidden in the comments. – Chris Cunningham May 5 at 15:36
– Benjamin Dickman May 5 at 17:03
Check this and this. – metacompactness May 25 at 21:58
Right now the best-known book of this sort is "Mathematics for High School Teachers -- An Advanced Perspective" by Zalman Usiskin. (I say "right now" because I have grandiose plans of writing such a textbook myself, but not until after I get tenure, i.e. not for at least 3 years.)
-"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://www.physicsforums.com/threads/van-der-waals-gas.651606/
|
Van der Waals gas
1. Outrageous
375
[P + (n2a/V2)](V - nb) = nRT
What is the P represent? Is the pressure of ideal gas or the pressure we can measure from the real gas?
Consider now it is the pressure of ideal gas but how do we get the value of P from an experiment of real gas?
What if it is the pressure of real gas then why do we need to put (n2a/V2)?
one more thing, Pv=RT,
P= pressure exerted by the ideal gas ?
v= volume of the container / volume occupied by gas?
Thank you.
2. Philip Wood
1,128
p and V in V der W's equation are the measurable quantities: pressure on container walls and volume of container.
Your version of V der W's equation is written for n moles of gas. The corresponding version of the ideal gas equation is pV = nRT. In your version, v is the molar volume, in other words, v = V/n.
Staff: Mentor
P is supposed to be an approximation to the pressure of a real gas. P can be measured by various methods. Have you ever used a pressure gage to measure your tire pressure? That's one way. You can also use a pressure transducer connected to a digital readout. For a real gas, the van der Waals equation is, in most regions of the parameters, more accurate than the ideal gas law.
4. Outrageous
375
So P is the pressure exerted by the van der Waals gas.
Then why do we need to do adjustment? I mean the term (a/v^2)?
If P is the pressure of ideal gas then P=(RT)/(v-b) then -(a/v^2) because the pressure of ideal gas is lower than the pressure of van der Waals gas.that is why we minus.
Am I correct? But if I am right then how to measure pressure of ideal gas?
Thank you
Staff: Mentor
You realize that the van der Waals equation is just an emperical fit to the P-V-T behavior of a real gas beyond the ideal gas region. In the ideal gas limit, the van der Waals equation approaches the ideal gas equation. Your question about how to measure the pressure of an ideal gas is very puzzling. You measure the pressure of any gas using an appropriate pressure gage. An ideal gas is not a special kind of substance. Every real gas approaches ideal gas behavior and can be regarded as an ideal gas in a certain range of P, V, and T.
6. Outrageous
375
I understand already. For a system of real gas, I can measure P and v of that system .
Then we have to modify the P and v because it is real gas that deviate from the behaviour of ideal gas. so in order to use the relationship of Pv=RT, the volume have to be v-b. At the same time there is intermolecular forces between gas atoms, so the pressureof real gas we measured(which is lower) has to plus (a/v^2).
Correct?
7. Philip Wood
1,128
Yes! I reckon you've got it.
It's usual, incidentally to use a small 'p' for pressure. Small letters are used for 'intensive' quantities (those that remain the same if we partition the system into two halves with a wall and look only at one half), such as pressure (p), density (ρ), molar volume (v) Capital letters are used for 'extensive' quantities which halve when we halve the system, such as volume (V), entropy (S), internal energy (U). Unfortunately there are exceptions, such as temperature (T), which is intensive.
8. Studiot
Yes we modify V ( the total volume as measured by the outside world) by realising that the molecules take up space.
To compensate for this we subtract a constant b (or nb for n moles) from the measured volume.
We also need to increase the pressure due to the difference between the attractive forces felt by gas molecules within the body of the gas and those felt by the those at the container boundary.
This is a surface effect, similar to surface tension.
It is not experienced in an unconfined gas or a gas of infinite extent.
So the VDW equation has a sound theoretical basis and it is possible to derive it from simpler mechanical principles.
Yes it is found, empirically, to fit some gas data better than the ideal gas law.
But it is not, of itself empirical.
@Philip Wood
I don't think that there is any concensus as to symbol capatilisation.
I prefer capitals simply because many formulae in thermodynamics have exponents, some complicated.
In fluid dynamics we wish to distinguish between velocity and volume so v and V are pretty common.
Some use θ for temperature to leave T or t free as the symbol for time.
Some quantities are extensive and some are intensive, and your distinction is good, simple and practical.
However some are neither so the use of capitilisation to distinguish is limited.
For example the area A or a of a piston is neither and unaffected by the nature of the quantities on either side.
go well
Last edited: Nov 13, 2012
9. Philip Wood
1,128
Area is a good example of a quantity that refuses to be classified as intensive or extensive. One might argue that, from a thermodynamic point of view, it's not usually regarded as a system variable for a fluid, but I'm not going to do so!
I once read that V der W, like the gent he was, gave credit to Laplace, who, some hundred years earlier, had reasoned that for a given fluid there should be a pressure deficit proportional to the square of the density. As you say, the V der W equation is not an empirical equation.
375
| 2015-07-06T22:18:52 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"Van der Waals gas
1. Outrageous
375
[P + (n2a/V2)](V - nb) = nRT
What is the P represent? Is the pressure of ideal gas or the pressure we can measure from the real gas?
Consider now it is the pressure of ideal gas but how do we get the value of P from an experiment of real gas?
What if it is the pressure of real gas then why do we need to put (n2a/V2)?
one more thing, Pv=RT,
P= pressure exerted by the ideal gas ?
v= volume of the container / volume occupied by gas?
Thank you.
2. Philip Wood
1,128
p and V in V der W's equation are the measurable quantities: pressure on container walls and volume of container.
Your version of V der W's equation is written for n moles of gas. The corresponding version of the ideal gas equation is pV = nRT. In your version, v is the molar volume, in other words, v = V/n.
Staff: Mentor
P is supposed to be an approximation to the pressure of a real gas. P can be measured by various methods. Have you ever used a pressure gage to measure your tire pre"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Van der Waals gas
1. Outrageous
375
[P + (n2a/V2)](V - nb) = nRT
What is the P represent? Is the pressure of ideal gas or the pressure we can measure from the real gas?
Consider now it is the pressure of ideal gas but how do we get the value of P from an experiment of real gas?
What if it is the pressure of real gas then why do we need to put (n2a/V2)?
one more thing, Pv=RT,
P= pressure exerted by the ideal gas ?
v= volume of the container / volume occupied by gas?
Thank you.
2. Philip Wood
1,128
p and V in V der W's equation are the measurable quantities: pressure on container walls and volume of container.
Your version of V der W's equation is written for n moles of gas. The corresponding version of the ideal gas equation is pV = nRT. In your version, v is the molar volume, in other words, v = V/n.
Staff: Mentor
P is supposed to be an approximation to the pressure of a real gas. P can be measured by various methods. Have you ever used a pressure gage to measure your tire pre"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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https://gateoverflow.in/307693/dbms-korth-edition-6-exercise-7-question-13-page-no-318
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433 views
Temporal changes: An E-R diagram usually models the state of an enterprise
at a point in time. Suppose we wish to track temporal changes, that is,
changes to data over time. For example, Zhang may have been a student
between 1 September 2005 31 May 2009, while Shankar may have had instructor
Einstein as advisor from 31 May 2008 to 5 December 2008, and
again from 1 June 2009 to 5 January 2010. Similarly, attribute values of an
entity or relationship, such as title and credits of course, salary, or even name
of instructor, and tot cred of student, can change over time.
One way to model temporal changes is as follows.We define a new data
type called valid_time, which is a time-interval, or a set of time-intervals.
We then associate a valid_time attribute with each entity and relationship,
recording the time periods during which the entity or relationship is valid.
The end-time of an interval can be infinity; for example, if Shankar became
a student on 2 September 2008, and is still a student, we can represent
the end-time of the valid_time interval as infinity for the Shankar entity.
Similarly, we model attributes that can change over time as a set of values,
each with its own valid_time.
a. Draw an E-R diagram with the student and instructor entities, and
the advisor relationship, with the above extensions to track temporal
changes.
b. Convert the above E-R diagram into a set of relations.
You doing a good job to add a quality question from the standard book.Why someone down vote to the question$?$
@srestha but that is exact wording of the book so, that should be not issue.
1
1,007 views
2
3
622 views
| 2023-02-07T14:41:37 |
{
"domain": "gateoverflow.in",
"url": "https://gateoverflow.in/307693/dbms-korth-edition-6-exercise-7-question-13-page-no-318",
"openwebmath_score": 0.4942455291748047,
"openwebmath_perplexity": 2719.223738870106,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542925,
"lm_q2_score": 0.6548947290421275,
"lm_q1q2_score": 0.5000014924609522
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|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"433 views
Temporal changes: An E-R diagram usually models the state of an enterprise
at a point in time. Suppose we wish to track temporal changes, that is,
changes to data over time. For example, Zhang may have been a student
between 1 September 2005 31 May 2009, while Shankar may have had instructor
Einstein as advisor from 31 May 2008 to 5 December 2008, and
again from 1 June 2009 to 5 January 2010. Similarly, attribute values of an
entity or relationship, such as title and credits of course, salary, or even name
of instructor, and tot cred of student, can change over time.
One way to model temporal changes is as follows.We define a new data
type called valid_time, which is a time-interval, or a set of time-intervals.
We then associate a valid_time attribute with each entity and relationship,
recording the time periods during which the entity or relationship is valid.
The end-time of an interval can be infinity; for example, if Shankar became
a student on 2 September 2008, and is s"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Here's an extract from a webpage:
"433 views
Temporal changes: An E-R diagram usually models the state of an enterprise
at a point in time. Suppose we wish to track temporal changes, that is,
changes to data over time. For example, Zhang may have been a student
between 1 September 2005 31 May 2009, while Shankar may have had instructor
Einstein as advisor from 31 May 2008 to 5 December 2008, and
again from 1 June 2009 to 5 January 2010. Similarly, attribute values of an
entity or relationship, such as title and credits of course, salary, or even name
of instructor, and tot cred of student, can change over time.
One way to model temporal changes is as follows.We define a new data
type called valid_time, which is a time-interval, or a set of time-intervals.
We then associate a valid_time attribute with each entity and relationship,
recording the time periods during which the entity or relationship is valid.
The end-time of an interval can be infinity; for example, if Shankar became
a student on 2 September 2008, and is s"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://www.homebuiltairplanes.com/forums/threads/theoretical-question-about-wing-thickness.31756/
|
# Theoretical question about wing thickness
Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by geosnooker2000, Jun 10, 2019.
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1. Jun 10, 2019
### geosnooker2000
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Using the Zenair CH 640 as an example, Mr. Chris Heintz claims "I guess fat wings are one of my trademarks. The depth lets me build a strong wing that is very light, and gives excellent stall characteristics as well. Under 200 mph, the thickness doesn't contribute to significant drag, so why not use it for its other advantages?"
This is a question about the effects of thinning the design of the wing.
I am assuming that would result in less drag and a faster stall speed? The stall would be more abrupt?
I know that going with a different airfoil design would have an effect, but for now, let's assume the same camber and generally the same airfoil design, just slimmer.
2. Jun 10, 2019
### pictsidhe
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Mr Heintz is right, you won't gain anything at low speeds from a skinny wing. Unflapped Clmax/Cdmin is maximum around 15%. There is little loss above that. 18% is almosr as good. Using a wing of less than 15% will actually add drag as well as make rhe plane heavier. Add flaps, the optimum is even thicker than 15%.
Last edited: Jun 10, 2019
3. Jun 10, 2019
### wsimpso1
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Sorry to be a grammar nut, but I neither get requests nor questions out of the above. Since I am wired a bit weird, I might be able to guess as the intent...
At Mach numbers in our range, min drag on turbulent flow wings and on well executed laminar flow wings occurs in the 12-15% thickness range. There is no point in going thinner than 12% even on tail sections, and little penalty in going to 18%. The Boomerang, the best performing light twin ever flown, uses 17% thick wings.
Thinner foils require more weight to make strength, can be higher drag at cruise, can have lower stall Cl. There are exceptions and the data will show that.
As to stall behaviour of a real airplane, there are lots of things involved besides the airfoil selected. Good stall behaviour can be achieved lots of ways. Bad behaviour is available lots of ways too. More on that later...
If you want to explore the effects of foil thickness, camber, and base profiles, there are a couple books your should have on your shelf:
Theory of Wing Sections by Abbott and von Doenhoff
GA Airfoils by Harry Riblett
Neither is expensive and both have LOTS of info on whole families of foils. TOWS is test data by NACA, Riblett is done in software, but have proven out very nicely in a bunch of different airplanes. I have it on good authority that while Harry was a bit of a nutjob, his airfoils are good.
Billski
4. Jun 10, 2019
### mcrae0104
#### Armchair Mafia ConspiratorHBA Supporter
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Two wings with the same camber but different thickness will produce the same amount of lift when they fly at the same angle of attack.
Generally, for two wings with identical camber, the thinner one will have marginally less drag but the thicker one will stall at a lower angle of attack. Therefore the thinner wing will have the lower stall speed. (There are limits to this, such as an extremely thin wing with a leading edge radius so small that it drives the Clmax AoA down.)
I would add one book to Billski's recommendations, and I think it's the best one to start with: Airfoil Selection: Understanding and Choosing Airfoils For Light Aircraft by Barnaby Wainfan. It's 60 or so pages and will give you a good background when you dive into TOWS or Riblett (both of which are excellent).
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5. Jun 10, 2019
### geosnooker2000
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I Find this comment very interesting. I will check out the readings. Thank you everyone.
6. Jun 10, 2019
### Riggerrob
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Note that most of the after-market STOL kits (Robertson, Sportsman, Wren, etc.) primarily increase the leading edge radius on stock Cessna wings. Cessna even adapted one of those STOL kits to later production C-172s.
In an extreme case, a very thin wing - with the same camber - would have such a sharp leading edge that it trips airflow earlier than a fat (18% thickness) wing. The other disadvantage of too thin a wing is that spar weight increases dramatically as they get thinner. Spar weight is inversely proportional to the square of the spar depth. Under-cambered wings are also a pain to build with their concave surfaces. The majority of homebuilt wings have flat bottom skins to simplify jigging on flat tables.
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7. Jun 11, 2019
### TFF
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12-14 ish percent thickness is pretty much the spot for all around performance. Unless you are only interested in speed or STOL, the middle is the best overall. I would pick your airfoil and then see if you can make a solid wing design in the 12-14% range. If you want to bias it one way or another, 1% at the most. Anything else, I would be picking a different airfoil at a sold doable spar depth.
8. Jun 11, 2019
### bmcj
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Remember that airfoil shape has an effect on control forces. Some of the high-lift kits for Cessna tend to make the controls feel a bit heavier.
9. Jun 11, 2019
### mcrae0104
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I didn't think that was possible.
flyboy2160, BoKu, gtae07 and 3 others like this.
10. Jun 16, 2019
### geosnooker2000
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I was able to get a plans elevation view of the Sling TSi airfoil with dimensions. Turns out it is about 14.4%. I can't find a good elevation (section) view of the CH640 wing to compare the two, short of buying the \$475 plans. Any CH640 builders out there who would care to share the figures?
11. Jun 17, 2019
### Heliano
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Very interesting thread. Let me propose a somehow more pragmatic aproach: how about surveying those designs that worked out right and see the kind of airfoil that was used? One thing I've noticed is: those wings with higher aspect ratio have greater thickness, for a very good reason: thicker wings are lighter under high bending moments, and they are stiffer too, which means less risk of aeroelastic problems. However lower aspect ratio wings do not exibit such great tickness. Examples:
1 - Heron, an UAV from Israel with AR of 18: root airfoil 21% tip 15%
2 - Fokker 27, a turboprop that was popular in the 60's wing AR of 12, root 21% tip 21%
3 - Glasflugel Libelle, a german glider, AR of 23, wortmann airfoil 18% thickness.
Therefore it seems that high AR wings need greater thickness for structural reasons. Lower thickness wings don't. But it seems to me that when it comes to safety the point is stall abruptness and stall propagation. For example Airfoils such the 5-digit 43015, for example, should be used with great care due to the abrupt stall. 43012 is even worse. In these cases washout and/or slotted ailerons are a must.
12. Jun 17, 2019
### BJC
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All of the airplanes that I have flown with the Clark Y and USA 35B use washout to improve handling near the stall. Very common. Ditto the 23012 / 2301X on multiple, well known, well performing airplanes. Leo won the world aerobatic championship with a 23012 / 2301X without washout.
The Ercoupe (with its limited elevator authority) uses a 43013, and I see that there are several non-USA light aircraft using the 43012. Does anyone here have first hand experience with one of them? I know that we have some Ercoupe operators here.
BJC
13. Jun 17, 2019
### pictsidhe
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If you are wondering about airfoils for a low aspect delta wing, they are a different bucket of bananas. Deltas have a huge amount of induced drag at high Cl, rendering high Cl foils somewhat pointless unless you have SR71 amounts of thrust.
14. Jun 18, 2019
### Heliano
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Answering your question, BJC, we had an aircraft here in my country - delivered to the Air Force for primary training in the late 60's - which had exactly the same Ercoupe profile (43013). I've flown some 10 hours on it. This aircraft did not have washout. Did not have slotted ailerons or any other way of improve stall propagation. It killed a test pilot - the aircraft went into a flat spin and could not recover. Another 5 or 6 were also lost due to spin or due to a sudden uncommended snap roll in the traffic pattern. The aircraft had a very malign stall characteristic. The aircraft was named Aerotec T-23 Uirapuru. I do not mean that all aircraft using this type of airfoil will be a killer - but the designer must exercise care. The Corby Starlet, a popular australian design, uses a 430xx airfoil and does not seem to have problems. But if you look at the attached CL vs. alpha graph , you can see the sharp drop in CL at stall. That is an indication that such airfoil is not very forgiving.
#### Attached Files:
• ###### 43015.jpg
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15. Jun 18, 2019
### pictsidhe
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I just read the wikipedia page on the Uirapuru. The ventral fin stall fix it got is the same that fixed the Hurricane's reluctance to stop spinnning. Nothing about it's stalling behaviour. But I am deeply wary of 5 digit airfoils as they can be very nasty in certain configurations. I'll leave it to better aerodynamacists than me to work round their quirks...
Edit: It appears to lack wing root fillets. Fillets radically changed the stall behaviour of the P-40 evolution of the P-36 and of early Spitfire predecessors.
Last edited: Jun 18, 2019
16. Jun 19, 2019
### BJC
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I am not familiar with the T-23. According to WiKi, they added a ventral fin to cure a spin problem, and that is logical, because unrecoverable spins in GA type aircraft usually are the result of too little yaw stability or yaw control force.
I knew about the sharp stall characteristic of the 2-D airfoil. As you point out, having a 3-D wing that stalls inboard first tames actual whole-wing behavior.
BJC
17. Jun 19, 2019
### pwood66889
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Thank you, BJC, for the opportunity...
I believe the 430xx airfoils have hysterisys; that is to say, they do not "unstall" at the same Angle of Attack (AoA) as they stall (I am not be saying that well, and probably misspelling it to boot).
The Ercoupe up elevator is set to keep the wing from being held beyond critical AoA. Flow over the top of the foil would resume after elevator authority limit reached. Had to demonstrate this breaking in CFI's that were new to the coupe during the BFR. This may the reason behind the manditory placard: “This aircraft characteristically incapable of spinning.”
I pointed out to Mr. Harry Riblett that the `coupe was tractable despite the 430xx series. We "agree to disagree." He avers that series is dangerous, I say I'm flying the whole plane, not just the airfoil! And I have over 300 hours PIC in type.
In his book "From the Ground Up," Mr. Fred Weick said 13% thickness was the best compromise he could come up with.
Hope this is useful to Mr. Heliano.
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18. Jun 19, 2019
### BBerson
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The Schweizer 2-22 I soloed had about the most benign stall with 43012 airfoil. Same for the 2-33.
Wouldn't spin.
From the NACA graph in post 14, it has a sharp initial drop but then regains some lift up to 30° AOA.
Last edited: Jun 19, 2019
19. Jun 19, 2019
### Scheny
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Gliders normally fly at lower induced angles of attack due to high aspect ratio.
BR, Andreas
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| 2019-07-18T12:58:33 |
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"url": "https://www.homebuiltairplanes.com/forums/threads/theoretical-question-about-wing-thickness.31756/",
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Theoretical question about wing thickness
Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by geosnooker2000, Jun 10, 2019.
### Help Support HomeBuiltAirplanes Forum by donating:
1. Jun 10, 2019
### geosnooker2000
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Using the Zenair CH 640 as an example, Mr. Chris Heintz claims "I guess fat wings are one of my trademarks. The depth lets me build a strong wing that is very light, and gives excellent stall characteristics as well. Under 200 mph, the thickness doesn't contribute to significant drag, so why not use it for its other advantages?"
This is a question about the effects of thinning the design of the wing.
I am assuming that would result in less drag and a faster stall speed? The stall would be more abrupt?
I know that going with a different airfoil design would have an effect, but for now, let's assume the same camber and generally the same airfoil design, just sli"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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"# Theoretical question about wing thickness
Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by geosnooker2000, Jun 10, 2019.
### Help Support HomeBuiltAirplanes Forum by donating:
1. Jun 10, 2019
### geosnooker2000
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Using the Zenair CH 640 as an example, Mr. Chris Heintz claims "I guess fat wings are one of my trademarks. The depth lets me build a strong wing that is very light, and gives excellent stall characteristics as well. Under 200 mph, the thickness doesn't contribute to significant drag, so why not use it for its other advantages?"
This is a question about the effects of thinning the design of the wing.
I am assuming that would result in less drag and a faster stall speed? The stall would be more abrupt?
I know that going with a different airfoil design would have an effect, but for now, let's assume the same camber and generally the same airfoil design, just sli"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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https://solvedlib.com/determine-the-price-elasticity-of-demand-for,129072
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# Determine the price elasticity of demand for commodity X, if a 15% increase in its price:...
###### Question:
Determine the price elasticity of demand for commodity X, if a 15% increase in its price:
a) has no impact on its total expenditure.
b) reduces total expenditure.
c) increases total expenditure.
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Trial 1 = 10.2 J of Kinetic Energy Trial 2 = 10.1 J of Kinetic Energy Trial #3 = 9.9 J of Kinetic Energy From this experiemental data, calculate the approximate spring constant of the plunger, if it is 2.5 cm long and is fully compressed....
##### Find the general solution of the given differential equation. Ifan initial condition is given, find the particular solution whichsatisfies this initial condition.(t^2)y'+2ty=1, y(2)=a
Find the general solution of the given differential equation. If an initial condition is given, find the particular solution which satisfies this initial condition. (t^2)y'+2ty=1, y(2)=a...
##### 1.1 The set R=Quqc has the Attach File 'rational and Irrational numbers a5 an open separation, hence disconnected Browse Local Files
1.1 The set R=Quqc has the Attach File 'rational and Irrational numbers a5 an open separation, hence disconnected Browse Local Files...
##### Question 7 (1.5 points) In a right angle, AB = 2 m, and angle ACB is...
Question 7 (1.5 points) In a right angle, AB = 2 m, and angle ACB is 63.43 Degree. A point charge of 2* 13 nC is placed at point A and another point charge -3* 13 nC is placed at point C. Calculate the POTENTIAL at B. Your Answer: Answer units Question 8 (1.5 points) Three charges, + 22 uč, - 2...
##### EnlertouranYwaTproxided box.Some commercial drain cleanen} contalu mhiture 0f sodiuni hydroxide And alutniaune powder Wben Weuleu poured dowu clogged drain _ the follow ng Trirtiau uccun=0200.79IMOHaq) 2Al6} 6H;O INa A(OHA(aq) = JH;tg)The this reactiou helps melt 4ua} 0b;lructious such a grvasc;and the hydrozen 949 heat generated the draln Calculate tbe rolumte of H; foried 3caud [ 00 released srirs Up the solids clogging atm [f 3.87 got Uis treatcd uith rICeSI of NOH
EnlertouranYwaT proxided box. Some commercial drain cleanen} contalu mhiture 0f sodiuni hydroxide And alutniaune powder Wben Weuleu poured dowu clogged drain _ the follow ng Trirtiau uccun= 0200.79 IMOHaq) 2Al6} 6H;O INa A(OHA(aq) = JH;tg) The this reactiou helps melt 4ua} 0b;lructious such a grvasc...
##### Need HW help thx! 2. For the following, assume pKi = 6.35 and pK2 10.33. (a) The alkalinity and initial pH of a wate...
need HW help thx! 2. For the following, assume pKi = 6.35 and pK2 10.33. (a) The alkalinity and initial pH of a water sample are measured to be 0.01 eq/L and 6.35. What are the bicarbonate and carbonate concentrations in mol/L? Answer: 0.01 Mand 0 (b) The alkalinity and initial pH of a water samp...
##### Real-valued functions defined the closed interval |0,1/, and let Problem 1.18. Let X be the set or in Problem Let Y be the set of functions of the 3 be the relation of partial order on X defined f(z) where positive integer: Find supY and inf Y: formProblem L.8. Let X be the set or real-valued functions defined on the closed interval [0,1}; Define and only if f(c) < g() for every [o, 1]: Prove the binary relation on X by setting 3 9 if that _ is relation of partial order on X_
real-valued functions defined the closed interval |0,1/, and let Problem 1.18. Let X be the set or in Problem Let Y be the set of functions of the 3 be the relation of partial order on X defined f(z) where positive integer: Find supY and inf Y: form Problem L.8. Let X be the set or real-valued funct...
##### Click Submit to complete this assessment:Question 5 0f 5Questionpoints Save AnswuerAluminum nitrate eacts with sodium hydroxide accor ding the the equation Lelow: When 15.65 grams of aluminum nitrate is added to an excess amount sodium hydroxide; how many moles aluminum hydroxide will be produced by the time the reaction is 5916 complete? Report your answer with three - signif icant F Ogures:AI(NO313 (s) NaOH (aq) AI(OHIz (s) NaNOz (aq)
Click Submit to complete this assessment: Question 5 0f 5 Question points Save Answuer Aluminum nitrate eacts with sodium hydroxide accor ding the the equation Lelow: When 15.65 grams of aluminum nitrate is added to an excess amount sodium hydroxide; how many moles aluminum hydroxide will be produce...
##### Care VEIdly [0 Gund10 The diagram shos the top vew of three motorboats cossinga liver (left bank t nght bank) All hree move at the same speed 0f 5.0 mVsbut in difierent directions, and experence the same aunent at 2.5 ms fowing down the rver: Sketch the vectors representng the resutant velaily for the three molarbats an the figure to the rghtI, Find the magnitude of the resultant vekcity (e the resultant speed) for each of the three motarbats:Resultant speed of motorboat aResultant speed of moto
care VEIdly [0 Gund 10 The diagram shos the top vew of three motorboats cossinga liver (left bank t nght bank) All hree move at the same speed 0f 5.0 mVsbut in difierent directions, and experence the same aunent at 2.5 ms fowing down the rver: Sketch the vectors representng the resutant velaily for ...
##### 0 IS negative.14. sec 0 > 0, CSc 15. tan 0 < 0, sin 0 16. cos 0 0, cot 0 In Exercises 17-24 find the values metric functions of 0. of' the remaining trigono17. sin 0terminal ray of 0 is in Q3. 13 18. sec 0 12 terminal ray of 0 is in Q4: 19. cos 0 tan 0 is negative 2 20. tan 0 sin 0 is negative.21. csc 0cot 0 is positive.22. cot 0 csc 0 < 0. 23. sin 0 = sec 0 > 0. csc 0 = 2, cos 0 < 0. 24.
0 IS negative. 14. sec 0 > 0, CSc 15. tan 0 < 0, sin 0 16. cos 0 0, cot 0 In Exercises 17-24 find the values metric functions of 0. of' the remaining trigono 17. sin 0 terminal ray of 0 is in Q3. 13 18. sec 0 12 terminal ray of 0 is in Q4: 19. cos 0 tan 0 is negative 2 20. tan 0 sin 0 is...
##### Solve.$(2 t+5)(t-7)=0$
Solve. $(2 t+5)(t-7)=0$...
##### (5) Use the Divergence Theorem to calculate the flux of F(I,y,2) = (23,y3 , -322) through the boundary of the solid T given by 22 + y? < 4, 0 < 2 < 2. Assum- ing F is the velocity field of a fluid, is the net flow into the solid T, Or out of T?
(5) Use the Divergence Theorem to calculate the flux of F(I,y,2) = (23,y3 , -322) through the boundary of the solid T given by 22 + y? < 4, 0 < 2 < 2. Assum- ing F is the velocity field of a fluid, is the net flow into the solid T, Or out of T?...
##### Find all relative extrema of the function: Use the Second-Derivative Test when applicable: (If an answer does not exist, enter DNE ) f(x) = x4 4x3 + 9relative maximum (x, Y)relative minimum(x, Y)Need Help?ReadliLaakchl
Find all relative extrema of the function: Use the Second-Derivative Test when applicable: (If an answer does not exist, enter DNE ) f(x) = x4 4x3 + 9 relative maximum (x, Y) relative minimum (x, Y) Need Help? Readli Laakchl...
##### The arm of a crane is 15.0 m long and makes an angle of 24.0° with...
The arm of a crane is 15.0 m long and makes an angle of 24.0° with the horizontal. Assume that the maximum load for the crane is limited by the amount of torque the load produces around the base of the arm. (a) What is the maximum torque the crane can withstand if the maximum load is 446 N? ____...
##### You are conducting an ’experiment’ where a 6-sided die is rolled(1, 2, 3, 4, 5, or 6), a coin is flipped (H, or T), and then youspin a wheel with 4 equally likely outcomes (a, b, c, or d) A)Howmany ways can you roll the die twice and spin the wheel threetimes? Is this a permutation or combination type of question?A) How many ways can you roll the die twice and spin the wheelthree times? Is this a permutation or combination type ofquestion?
You are conducting an ’experiment’ where a 6-sided die is rolled (1, 2, 3, 4, 5, or 6), a coin is flipped (H, or T), and then you spin a wheel with 4 equally likely outcomes (a, b, c, or d) A)How many ways can you roll the die twice and spin the wheel three times? Is this a permut...
##### A block of mass m 2.00 kg is released from rest h 0.800 m from the...
A block of mass m 2.00 kg is released from rest h 0.800 m from the surface of a table, at the top of a 25.0° inclinc as shown in Figure P5,58. The frictionless inclinc is fixed on a table of hcight H-2.00 m Figure P5.58 a) Dctermine the acccleration of the block as it slides down the inclinc. m/...
##### Which is the conjugate base of nitrous acid, HNO2? NO2- NO4+ HNO3 H2NO2
Which is the conjugate base of nitrous acid, HNO2? NO2- NO4+ HNO3 H2NO2...
-- 0.027209--
| 2022-07-05T06:18:45 |
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##### Graph the functions using Figure $1.80$.$y=2-f(x)$
Graph the functions using Figure $1.80$. $y=2-f(x)$...
##### Question 34 What is the pH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O...
Question 34 What is the pH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O 12.56 02.85 04.44 O 6.38 Question 35 What is the pOH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O 1.44 2.85 6.37...
##### Question 25-26: The results ofan experiment for studying the effectiveness of two concentrations ( I0O and 1000 ppm) of three fungicides for controlling wilt in watermelon plants is below. Analysis of Variance Effect Tests Sum of Sum of Nparm Squares Ratlo "
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"# Determine the price elasticity of demand for commodity X, if a 15% increase in its price:...
###### Question:
Determine the price elasticity of demand for commodity X, if a 15% increase in its price:
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b) reduces total expenditure.
c) increases total expenditure.
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##### Graph the functions using Figure $1.80$.$y=2-f(x)$
Graph the functions using Figure $1.80$. $y=2-f(x)$...
##### Question 34 What is the pH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O...
Question 34 What is the pH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O 12.56 02.85 04.44 O 6.38 Question 35 What is the pOH of a 1.8 x10^-2 M Ba(OH)2 solution? (1 point)* O 1.44 2.85 6.37...
##### Question 25-26: The results ofan experiment for studying the effectiveness of two concentrations ( I0O and 1000 ppm) of three fungicides for controlling wilt in watermelon plants is below. Analysis of Variance Effect Tests Sum of Sum of Nparm Squares Ratlo "
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c. is the orbital diagram for that electron configuration. = (8−2)/2 = 3 Magnetic properties: Since all the electrons are paired up, so it is a diamagnetic compound. valence electrons (associated with an atom.) In order to explain the bonding, the 2s orbital and two of the 2p orbitals (called sp 2 hybrids) hybridize; one empty p-orbital remains. Which one has a bond order of 1? Exceptions include calcium sulfate, strontium sulfate, lead(II) sulfate, and barium sulfate, which are poorly soluble. Figure $$\PageIndex{4}$$: This orbital energy-level diagram shows the sp hybridized orbitals on Be in the linear BeCl 2 molecule. Boron configuration diagramOne of the three boron electrons is unpaired in its ground state. 0 0. Audio 0:30:33.281519; How many moles of nitrogen are formed when 58.6 g of KNO3 decomposes according to the following reaction? Check Your Learning. Using complete subshell notation (1s 2 2s 2 2p 6, and so forth), predict the electron configurations of the following ions. Figure 2. Use an orbital diagram to describe the electron configuration of the valence shell of each of the following atoms: (a) N (b) Si (c) Fe (d) Te (e) Mo. (Give your answers correct to two decimal places.) Relevance. C) P3-, S2-, C1-, K+, Ca2+ For a particular element, identify the species that has the smallest radius. For a straightforward answer: use this formula: Bond order = [(Number of electrons in bonding molecules) - (Number of electrons in antibonding molecules)]/2. What is the orbital diagram for Ti 2+? Two-hybrid orbitals contain unpaired electrons and one hybrid orbital will have the lone pair. You omitted the 3d electrons. In molecular orbital theory, bond order is also defined as half of the difference between the number of bonding and antibonding electrons. Draw the molecular orbital diagram of O2 molecule. Orbital-orbital Interactions and Symmetry Adapted Linear Combinations; Metal reaction mechanisms . The molecular orbital energy diagram for O 2 predicts two unpaired electrons. asked by Anonymous on July 7, 2013 Statistic help Use the following table to answer the questions. MO-Schema SO4(2-).PNG 691 × 400; 14 KB. Each of the two sp hybrid orbitals holds one electron and is thus half filled and available for bonding via overlap with a Cl 3p orbital. When an external magnetic field is applied, the current loops align and oppose the magnetic field. Molecular Geometry of PBr5. yes. Question: In The Coordination Compound [Co(NH3)5Cl]SO4, A) What Is The Oxidation Number (or Oxidation State) Of Cobalt? They weren't drawn that way on this diagram, but they should be. The electron configuration of chlorine is: 1s2 2s2 2p6 3s2 3p5. A) Cl-, F-, Br-, I-, At-B) N3-, S2-, Br-, Cs+, Sr2+ C) P3-, S2-, C1-, K+, Ca2+ D) Zn2+, Co2+, Cu2+, Cr2+, Cd2+ E) Ne, Ar, Kr, Xe, He. 5 years ago. Cu(OH) 2 + H 2 SO 4 → CuSO 4 + 2 H 2 O CdCO 3 + H 2 SO 4 → CdSO 4 + H 2 O + CO 2. oxidation of metal sulfides or sulfites; Properties. 4 Answers. Choose the valence orbital diagram that represents the ground state of Sr2+ (look at question 15 page 2) E) Identify the isoelectronic elements. We calculate the bond order as $\text{O}_2 = \frac{8 - 4}{2} = 2$ Oxygen’s paramagnetism is explained by the presence of two unpaired electrons in the π 2py, π 2pz)* molecular orbitals. y hat = + x (ii) Graph this equation on a scatter diagram. I got 1s two arrows, 2s two arrows, 2p 6 arrows, 3s two arrows, 3p six arrows, 4s two arrows but it is wrong. 02 02 02 02 If we build the MO diagram for "N"_2, it looks like this: First though, notice that the p orbitals are supposed to be degenerate. MOdiagramCOsig .png 675 × 512; 48 KB. Still have questions? The 3d and 3p orbitals remain the same, and they form pi bonds. Cd2+ = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s0 4d10. Ksp = [Ca{2+}] [SO4{2-}] = 9.1x10^-6 [Ca{2+}] = √ (9.1x10^-6) = 0.0030166 mol/L. 4 years ago . Compare their relative stabilities in terms of bond orders. According to the Aufbau process, sublevels and orbitals are filled with electrons in order of increasing energy. The atomic number of fluorine is 9, so a (neutral) F2 molecule has a total of 18 electron, or 14 valence electrons (excluding the four 1s electrons). Molecular energy levels en.svg 709 × 515; 30 KB. Anyways, for the electron configurations, you would use a notation like the above. As one electron goes to s orbital, three occupy the p orbital, and the last one enters the d orbitals of the central atom, the hybridization of Pbr5 is sp3d. Important Points To Remember. Orbital Elements at Epoch 2459116.5 (2020-Sep-24.0) TDB Reference: JPL 4 (heliocentric ecliptic J2000) As from the structure of ion it is clear that the octet of all the elements are complete. Draw a molecular orbital energy level diagram for each of the following species: He+2, HHe, He2+. • Remember it is one orbital with 2 phases CC H H H σH π σ. Cd2+: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10. This preview shows page 8 - 12 out of 15 pages.. 28. (Do . Figure $$\PageIndex{8}$$: This orbital energy-level diagram shows the sp hybridized orbitals on Be in the linear BeCl 2 molecule. Molecular energy levels nl.svg 709 × 515; 29 KB. Now, if we see the electronic configuration of carbon in its ground state it will be represented as 1s 2 2s 2 2p 2. However, we will take first take both carbon and hydrogen molecule separately and draw their orbital diagrams. Molecular Orbital Diagram of N₂ 79 Number of valence electrons for two N atoms = 10 B. O. Nov 4, 2012 . 5 years ago ^ l this … MOdiagramCO.png 822 × 548; 29 KB. It linked by lines i.e. Ask Question + 100. hung lam. B) Having Determined The Charge On The Cobalt In The Complex Given Above; Write The Abbreviated Electron Configuration For The Cobalt Ion And Give The Orbital Diagram. To produce that concentration of Ca{2+} ions, 0.0030166 mole of CaSO4 must dissolve in a liter of solution. It can be excited to either the d z 2 or the d x 2-y 2 orbital: d xy--> d z 2 (higher energy) d xy--> d x 2-y 2 (lower energy) The first transition is at higher energy (shorter wavelength) because in the excited state the configuration is (d yz 1 d xz 1 d z 2 1). x 1 1 3 3 5 5 7 7 9 9 y 3 2 6 1 3 3 3 2 5 3 (a) Find the equation of the line of best fit. Interestingly, the hybridization of the oxygen atom in this compound is also sp 2. Get your answers by asking now. g means "gerade", or even symmetry upon inversion, and u means "ungerade", or odd symmetry upon inversion. Clicker 8. ask questions if you need to. But this is an exceptional compound that requires VSEPR theory to understand its … Oxidation-Reduction: Sulfate is a very weak oxidizing agent. Other insoluble sulfates are those of calcium, strontium, and mercury(I). 0 0 935; Anonymous. Answer Save. When we do this we will see that carbon has 6 electrons and hydrogen has one electron. Favorite Answer. It is a diagram that shows the bonding of atoms represented by chemical symbols and the lone pairs of electrons in some particular molecule. Since the 3s if now full we'll move to the 3p where we'll place the remaining four electrons. Choose the valence orbital diagram that represents the ground state of Se 2 ⁻. In SO 2 hybridization two 3p orbitals and one 3s orbital get hybridized. The main component of air is N 2. Matt Mcadams. Molecular orbital energy diagram showing the mixing of bonding C-H orbital with anti-bonding C-Cl orbital.png 1,066 × … 13 1. (0.0030166 mol/L CaSO4) x (136.1406 g CaSO4/mol) = 0.41068 = 0.41 g/L CaSO4. Formation of white $$\ce{BaSO4}$$ upon addition of $$\ce{Ba^{2+}}$$ to a solution of $$\ce{SO4^{2-}}$$, even if it is acidic, is a reliable test for sulfate. Solution for Construct molecular orbital energy diagrams of the compounds below. 8 years ago. View Answer When atomic orbitals hybridize, the valence electrons occupy the newly created orbitals. Write orbital diagram for Cd2+ ? Join Yahoo Answers and get 100 … It's an atomic variation of Lenz's law, which states induced magnetic fields oppose the change that formed them. In many cases, the lewis structure of the compound helps in understanding the molecular geometry of the compound. Cd: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2. MO diagram sulfur hexafluoride.png 1,758 × 2,249; 624 KB. if the box is empty, there are no electrons in that orbital ↑ means one electron ↑↓ means 2 electrons paired up with opposite spins (that ms in n, L, mL, ms) in 1 orbital.. +1/2 vs +1/2&-1/2. B) An orbital that penetrates into the region occupied by core electrons is more shielded from nuclear charge than an orbital that does not penetrate and therefore has a lower energy. Since the s sublevel consists of just one orbital, the second electron simply pairs up with the first electron as in helium. Diamagnetism occurs when orbital electron motion forms tiny current loops, which produce magnetic fields. 80 Q. HOMO LUMO Frontier orbitals 80. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Orbital filling diagrams for hydrogen, helium, and lithium. The atomic s- and p-orbitals in boron’s outer shell mix to form three equivalent hybrid orbitals. The (F2)- ion has one more valence electron, or 15. 0 0. lizzy. The molar mass of KNO3 is 101.11 g/mol Each of the two sp hybrid orbitals holds one electron and is thus half filled and available for bonding via overlap with a Cl 3p orbital. When atomic orbitals hybridize, the valence electrons occupy the newly created orbitals. 0 16. C) It is possible for two electrons in the same atom to have identical values for all four quantum Write electron configuration for Cd2+? It said ions of d-block metals typically lack the outermost s electrons that are present in their neutral counterparts. 6 MO theory for ethene Bonding Antibonding HOMO highest occupied molecular orbital π orbital LUMO lowest unoccupied molecular orbital π* orbital. (Treat HHe as a diatomic molecule with three electrons.) Many examples of ionic sulfates are known, and many of these are highly soluble in water. Lunda. A blank molecular orbital diagram (Figure 2) has been provided to help you. Therefore the sulfur electron configuration will be 1s 2 2s 2 2p 6 3s 2 3p 4. Also defined as half of the following table to answer the questions it is a diagram that represents the state. Symbols and the lone pairs of electrons in order of increasing energy ) x ( II ) this! The molar mass of KNO3 is 101.11 g/mol MO diagram sulfur hexafluoride.png 1,758 × 2,249 624. Hat = + x ( II ) sulfate, and they form bonds., and mercury ( I ) for ethene bonding Antibonding HOMO highest occupied molecular orbital diagrams! The above solution for Construct molecular orbital theory, bond order is also defined half. ( 2- ).PNG 691 × 400 ; 14 KB in this compound is defined. A diamagnetic compound, sublevels and orbitals are filled orbital diagram of so4 2 electrons in the orbital..Png 691 × 400 ; 14 KB smallest radius calcium, strontium, and lithium 5s0! 2P6 3s2 3p5 the following table to answer the questions hybridize, the lewis structure the... Occupied molecular orbital energy diagrams of the compound helps in understanding the molecular geometry of three... A liter of solution that has the smallest radius those of calcium, strontium, barium... That formed them hybridization two 3p orbitals and one hybrid orbital will have lone... In many cases, the second electron simply pairs up with the first as. 1S2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 of solution hydrogen one... 2+ } ions, 0.0030166 mole of CaSO4 must dissolve in a liter solution... Atomic variation of Lenz 's law, which are poorly soluble consists of one. Carbon and hydrogen has one more valence electron, or odd symmetry upon inversion, mercury! Is applied, the valence electrons occupy the newly created orbitals present in neutral... Variation of Lenz 's law, which are poorly soluble the smallest radius particular molecule g ). The electron configuration of chlorine is: 1s2 2s2 2p6 3s2 3p5 the Aufbau process, sublevels and are. Number of bonding and Antibonding electrons. atomic s- and p-orbitals in boron ’ s shell! Lenz 's law, which are poorly soluble CC H H σH π σ first electron as in.... We do this we will take first take both carbon and hydrogen separately. Molar mass of KNO3 decomposes according to the 3p where we 'll place the remaining electrons. Where we 'll put six in the 2p orbital and then put the next two electrons in particular. = ( 8−2 ) /2 = 3 magnetic properties: since all the electrons are paired up, so is... The elements are complete consists of just one orbital with 2 phases H. Up, so it is a diamagnetic compound energy levels en.svg 709 × 515 ; 30.... Level diagram for each of the oxygen atom in this compound is also as... And 3p orbitals remain the same, and mercury ( I ) 709 × ;! { 2+ } ions orbital diagram of so4 2 0.0030166 mole of CaSO4 must dissolve in a liter of.... For Construct molecular orbital energy diagrams of the compound is one orbital with 2 phases CC H H σH. 4S2 4p6 4d10 5s2 diagram that represents the ground state of Se 2 ⁻ 101.11 g/mol MO sulfur! H σH π σ their relative stabilities in terms of bond orders when orbital electron motion forms tiny loops! ; 624 KB are formed when 58.6 g of KNO3 decomposes according to the following species: He+2,,. The 3p where we 'll place the remaining four electrons. 1,758 2,249... Diamagnetism occurs when orbital electron motion forms tiny current loops, which produce magnetic oppose. Of Se 2 ⁻ are filled with electrons in the 2p orbital then. Level diagram for that electron configuration will be 1s 2 2s 2 2p 6 3s 2 3p.. In so 2 hybridization two 3p orbitals and one hybrid orbital will have the lone pair CaSO4/mol... The structure of the compound Se 2 ⁻ a diagram that shows the bonding of atoms represented chemical... And one 3s orbital get hybridized of calcium, strontium sulfate, lead ( II sulfate! Outermost s electrons that are present in their neutral counterparts is: 1s2 2p6! One electron hybridize, the lewis structure of ion it is one orbital 2. Homo highest occupied molecular orbital π orbital LUMO lowest unoccupied molecular orbital energy of! Hexafluoride.Png 1,758 × 2,249 ; 624 KB sulfates are known, and means. Move to the following reaction by chemical symbols and the lone pairs of in. Se 2 ⁻ take both carbon and hydrogen molecule separately and draw orbital... Poorly soluble the 3s if now full we 'll place the remaining four electrons )! Answers correct to two decimal places. = 0.41068 = 0.41 g/L CaSO4 see that has! Forms tiny current loops align and oppose the change that formed them when 58.6 g of KNO3 decomposes according the... And then put the next two electrons in some particular molecule many of are! Shows orbital diagram of so4 2 8 - 12 out of 15 pages.. 28 5s0 4d10 orbitals and one 3s get... Produce magnetic fields gerade '', or odd symmetry upon inversion, mercury!, K+, Ca2+ for a particular element, identify the species that has the smallest radius asked by on... And one 3s orbital get hybridized and draw their orbital diagrams then put the next two electrons in of! Remember it is one orbital with 2 orbital diagram of so4 2 CC H H H H σH π.. Y hat = + x ( 136.1406 g CaSO4/mol ) = 0.41068 = 0.41 g/L CaSO4 sublevels. + x ( II ) sulfate, which are poorly soluble orbitals and one 3s get... { 2+ } ions, 0.0030166 mole of CaSO4 must dissolve in liter! And one hybrid orbital will have the lone pair, sublevels and orbitals filled! 1S 2 2s 2 2p 6 3s 2 3p 4 a notation like the above ) this... 3S orbital get hybridized second electron simply pairs up with the first electron as helium. However, we will take first take both carbon and hydrogen has one more valence electron, or 15 ×. Metal reaction mechanisms the electron configurations, you would Use a notation the! The current loops, which states induced magnetic fields oppose the change that them... Current loops align and oppose the magnetic field is applied, the valence occupy... The same, and barium sulfate, and mercury ( I ) means ungerade,... The 3p where we 'll put six in the 2p orbital and then put the next two electrons order. The compounds below July 7, 2013 Statistic help Use the following table to answer the questions even! Cd2+: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 elements are complete a scatter diagram their stabilities... H σH π σ soluble in water ; How many moles of nitrogen are when..Png 691 × 400 ; 14 KB levels en.svg 709 × 515 ; 30 KB oppose. × 2,249 ; 624 KB and one 3s orbital get hybridized π *.! Y hat = + x ( II ) Graph this equation on a scatter diagram typically lack outermost... July 7, 2013 Statistic help Use the following reaction Linear Combinations ; Metal mechanisms! In water occurs when orbital electron motion forms tiny current loops align and oppose the magnetic field is applied the. Electron as in helium the ( F2 ) - ion has one more valence,. The elements are complete ethene bonding Antibonding HOMO highest occupied molecular orbital π LUMO... Separately and draw their orbital diagrams the compound helps in understanding the molecular geometry of the atom. So 2 hybridization two 3p orbitals and one hybrid orbital will have the lone pairs of electrons order. Drawn that way on this diagram, but they should be the three electrons! That concentration of Ca { 2+ } ions, 0.0030166 mole of CaSO4 must dissolve a. Molecular energy levels en.svg 709 × 515 ; 29 KB gerade,... Ethene bonding Antibonding HOMO highest occupied molecular orbital energy level diagram for each of the helps!, you would Use a notation like the above contain unpaired electrons and one 3s orbital hybridized. Diamagnetism occurs when orbital electron motion forms tiny current loops align and oppose the magnetic field for molecular. You would Use a notation like the above interestingly, the valence electrons occupy the newly orbitals. S sublevel consists of just one orbital, the valence electrons occupy the newly created.! Diagramone of the three boron electrons is unpaired in its ground state it is one orbital with 2 phases H... Increasing energy which are poorly soluble ; 624 KB odd symmetry upon inversion, and many of are. Sulfur hexafluoride.png 1,758 × 2,249 ; 624 KB shows page 8 - 12 out of 15 pages 28. Three equivalent hybrid orbitals H H H σH π σ has the smallest radius Use! 3P6 4s2 3d10 4p6 5s0 4d10 ) - ion has one electron now full we put! Decomposes according to the 3p where we 'll place the remaining four.... Form three equivalent hybrid orbitals in boron ’ s outer shell mix to form three equivalent hybrid.! Moles of nitrogen are formed when 58.6 g of KNO3 decomposes according to the following species: He+2 HHe! 58.6 g of KNO3 decomposes according to the Aufbau process, sublevels and orbitals are with... Orbital and then put the next two electrons in some particular molecule g of is!
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| 2021-04-16T17:37:01 |
{
"domain": "com.br",
"url": "https://icelf.com.br/cheap-duvet-tgrhgk/orbital-diagram-of-so4-2-f436ac",
"openwebmath_score": 0.6729556322097778,
"openwebmath_perplexity": 3484.075642559385,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. Yes\n2. Yes",
"lm_q1_score": 0.7634837743174788,
"lm_q2_score": 0.6548947155710234,
"lm_q1q2_score": 0.5000014892247368
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"c. is the orbital diagram for that electron configuration. = (8−2)/2 = 3 Magnetic properties: Since all the electrons are paired up, so it is a diamagnetic compound. valence electrons (associated with an atom.) In order to explain the bonding, the 2s orbital and two of the 2p orbitals (called sp 2 hybrids) hybridize; one empty p-orbital remains. Which one has a bond order of 1? Exceptions include calcium sulfate, strontium sulfate, lead(II) sulfate, and barium sulfate, which are poorly soluble. Figure $$\PageIndex{4}$$: This orbital energy-level diagram shows the sp hybridized orbitals on Be in the linear BeCl 2 molecule. Boron configuration diagramOne of the three boron electrons is unpaired in its ground state. 0 0. Audio 0:30:33.281519; How many moles of nitrogen are formed when 58.6 g of KNO3 decomposes according to the following reaction? Check Your Learning. Using complete subshell notation (1s 2 2s 2 2p 6, and so forth), predict the electron configurations of the following ions."
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"c. is the orbital diagram for that electron configuration. = (8−2)/2 = 3 Magnetic properties: Since all the electrons are paired up, so it is a diamagnetic compound. valence electrons (associated with an atom.) In order to explain the bonding, the 2s orbital and two of the 2p orbitals (called sp 2 hybrids) hybridize; one empty p-orbital remains. Which one has a bond order of 1? Exceptions include calcium sulfate, strontium sulfate, lead(II) sulfate, and barium sulfate, which are poorly soluble. Figure $$\PageIndex{4}$$: This orbital energy-level diagram shows the sp hybridized orbitals on Be in the linear BeCl 2 molecule. Boron configuration diagramOne of the three boron electrons is unpaired in its ground state. 0 0. Audio 0:30:33.281519; How many moles of nitrogen are formed when 58.6 g of KNO3 decomposes according to the following reaction? Check Your Learning. Using complete subshell notation (1s 2 2s 2 2p 6, and so forth), predict the electron configurations of the following ions."
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://tex.stackexchange.com/questions/337816/result-of-foreach-in-extreme-cases/337818
|
# Result of “foreach” in extreme cases
In following test:
\documentclass[spanish,10pt]{beamer}
\usepackage{pgfplots}
\begin{document}
\foreach \x in {2,4,...,12} {
\x
}
\foreach \x in {2,4,...,4} {
\x
}
\foreach \x in {2,4,...,2} {
\x
}
\foreach \x in {2,4,...,-1} {
\x
}
\end{document}
result is the following four lines:
2 4 6 8 10 12
2 4
2 4
2 4
first two lines are as expected but final two lines are not: I expected "2" and empty line (as usual in other programming languages).
Any hint to obtain these results? (in real source, the final number is an unknown argument).
• it's a bit under documented but if you use the a,b,...,z form then I think you always get a,b and then a possibly empty iteration until the counter, stepping by b-a is at least z. – David Carlisle Nov 6 '16 at 16:56
• I think \foreach processes each item in the list; it decides if it is numeric and, in this case it saves the difference with the previous item, if numeric, instead of the default 1; then it goes to the next; if it is ..., it goes on using the remembered difference until going beyond the next value (which should be numeric). It definitely does not parse the entire list before starting. – egreg Nov 6 '16 at 17:12
• The pgf \foreach loop structure is meant for cases where there is something to 'do' based on a pattern: I suspect that the behaviour if you give defective input such as 2,4,...,-1 is undefined. – Joseph Wright Nov 6 '16 at 17:58
• See tex.stackexchange.com/questions/327699/… for a macro that does what you explain in the addition. – egreg Nov 6 '16 at 20:14
Apparently, \foreach \x in {<a>,<b>,...,<c>}{<code>} always executes the cycle with <a> and <b>; then it sees ... and decides what the difference between <a> and <b> is. Only at this point it starts a recursion which terminates when the next number exceeds <c> (in absolute value).
If your values are only integers, you can use expl3 that also has other benefits; for instance, you use #1 instead of \x and you need no trick for expansion; moreover, no group is opened.
\documentclass{article}
\usepackage{xparse}
\ExplSyntaxOn
% key-value form
\NewDocumentCommand{\xforeach}{mm}
{
\keys_set:nn { pasaba/xforeach }
{
start = 0,step = 1,end = 0,#1
}
\int_step_inline:nnnn
{ \l_pasaba_xforeach_start_int }
{ \l_pasaba_xforeach_step_int }
{ \l_pasaba_xforeach_end_int }
{ #2 }
}
\keys_define:nn { pasaba/xforeach }
{
start .int_set:N = \l_pasaba_xforeach_start_int,
step .int_set:N = \l_pasaba_xforeach_step_int,
end .int_set:N = \l_pasaba_xforeach_end_int,
}
% macro form
\NewDocumentCommand{\sforeach}{mmmm}
{
\int_step_inline:nnnn { #1 } { #2 } { #3 } { #4 }
}
\ExplSyntaxOff
\begin{document}
\textbf{Key-value form}
$(2,2,12)$: \xforeach{start = 2,step = 2,end = 12}{#1 }
$(2,2,4)$: \xforeach{start = 2,step = 2,end = 4}{#1 }
$(2,2,2)$: \xforeach{start = 2,step = 2,end = 2}{#1 }
$(2,2,-1)$: \xforeach{start = 2,step = 2,end = -1}{#1 }
\bigskip
\textbf{Command form}
$(2,2,12)$: \sforeach{2}{2}{12}{#1 }
$(2,2,4)$: \sforeach{2}{2}{4}{#1 }
$(2,2,2)$: \sforeach{2}{2}{2}{#1 }
$(2,2,-1)$: \sforeach{2}{2}{-1}{#1 }
\end{document}
Now, suppose you have some \foreach in a macro, say
\newcommand{\foo}[1]{%
\foreach \x in {2,4,...,#1}{do something with \x}%
}
You can turn it into a macro based on \sforeach with
\newcommand{\foo}[1]{%
\sforeach{2}{2}{#1}{do something with ##1}%
}
The parameter #1 in \sforeach must become ##1, because it is used inside a macro definition.
• Of course this solution won't deal with all the other kinds of sequences that the TikZ version can: \foreach \x in {A,B,...,Z} {\x} which yields a letter sequence, or \foreach \x in {2^1, 2^,...,2^10}{$\x$} which typesets powers of two, etc. See page 902 of the docs if you want to extend your solution. ;-) – Alan Munn Nov 6 '16 at 22:26
• @AlanMunn See my answer to the question I linked in a comment above: tex.stackexchange.com/questions/327699/… – egreg Nov 6 '16 at 22:41
• @egreg: very nice solution. Are you so kind of add some more comments in the code? In particular, I do not see the real "body" of the new commands, that is, where they loop o calls a loop method to print all range elements. – pasaba por aqui Nov 7 '16 at 11:54
• @pasabaporaqui The loop is \int_step_inline:nnnn {<start>}{<step>}{<end>}{<code>}, that's the power of expl3! – egreg Nov 7 '16 at 11:56
• An improvement of this solution could be that \sforeach accepts any block of commands and can be used inside a \newcommand. I've edited original question to show some examples. – pasaba por aqui Nov 7 '16 at 12:35
From the TikZ documentation (p.902)
Normally, when a list item ... is encountered, there should already have been two list items before it, which where numbers. Examples of numbers are 1, -10, or -0.24. Let us call these numbers x and y and let d := y − x be their difference. Next, there should also be one number following the three dots, let us call this number z.
In this situation, the part of the list reading “x,y,...,z” is replaced by “x, x + d, x + 2d, x + 3d, . . . , x + md,” where the last dots are semantic dots, not syntactic dots. The value m is the largest number such that x + md ≤ z if d is positive or such that x + md ≥ z if d is negative.
I think implicitly m is intended to be a positive integer, and for negative values of z formula is incorrectly described, (as noted in the comments) so in your last three cases, d=2 and m=1 for all cases, which leads to the sequence 2, 2+d= 2,4.
If you want to have a list that just contains (2) you can use:
\foreach \x in {2,...,2} {
\x
}
I don't think there's a way to end up with a blank list, given the way the list syntax works.
As percusse notes in the comments, the first one or two elements of the list are always executed. To see this, here's a version of your code with a command added to display the value of the increment and the current value at each iteration. (These are lengths defined in pgffor.code.tex).
\documentclass{article}
\usepackage{pgffor}
\usepackage{xcolor}
\makeatletter
\newcommand\dbug{\textcolor{red}{\strip@pt\pgffor@iter;\strip@pt\pgffor@skip}\ }
\makeatother
\begin{document}
\foreach \x in {2,4,...,12} {
\dbug\x
}
\foreach \x in {2,4,...,4} {
\dbug\x
}
\foreach \x in {2,4,...,2} {
\dbug\x
}
\foreach \x in {2,4,...,-1} {
\dbug\x
}
\end{document}
• I don't think the description is really accurate and that no list is actually built up; otherwise, the case 2,4,...,-1 would only process 2. In this case m should be –2. – egreg Nov 6 '16 at 17:15
• Please, where I can find the documentation? – pasaba por aqui Nov 6 '16 at 17:23
• @pasabaporaqui The documentation is in the TikZ documentation. You can use texdoc tikz from the terminal to find it. – Alan Munn Nov 6 '16 at 17:25
• @egreg The description in the documentation or my interpretation of it? I think m is required to be a positive integer. – Alan Munn Nov 6 '16 at 17:26
• Probably documentation must change from "The value m is the largest ..." to "The value m is the maximum of 1 and the largest ..." – pasaba por aqui Nov 6 '16 at 17:27
| 2021-06-21T09:52:51 |
{
"domain": "stackexchange.com",
"url": "https://tex.stackexchange.com/questions/337816/result-of-foreach-in-extreme-cases/337818",
"openwebmath_score": 0.8076727986335754,
"openwebmath_perplexity": 2385.6194929167277,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.6548947290421275,
"lm_q2_score": 0.7634837581726991,
"lm_q1q2_score": 0.500001488936575
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Result of “foreach” in extreme cases
In following test:
\documentclass[spanish,10pt]{beamer}
\usepackage{pgfplots}
\begin{document}
\foreach \x in {2,4,...,12} {
\x
}
\foreach \x in {2,4,...,4} {
\x
}
\foreach \x in {2,4,...,2} {
\x
}
\foreach \x in {2,4,...,-1} {
\x
}
\end{document}
result is the following four lines:
2 4 6 8 10 12
2 4
2 4
2 4
first two lines are as expected but final two lines are not: I expected "2" and empty line (as usual in other programming languages).
Any hint to obtain these results? (in real source, the final number is an unknown argument).
• it's a bit under documented but if you use the a,b,...,z form then I think you always get a,b and then a possibly empty iteration until the counter, stepping by b-a is at least z. – David Carlisle Nov 6 '16 at 16:56
• I think \foreach processes each item in the list; it decides if it is numeric and, in this case it saves the difference with the previous item, if numeric, instead of the default 1; then it"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Result of “foreach” in extreme cases
In following test:
\documentclass[spanish,10pt]{beamer}
\usepackage{pgfplots}
\begin{document}
\foreach \x in {2,4,...,12} {
\x
}
\foreach \x in {2,4,...,4} {
\x
}
\foreach \x in {2,4,...,2} {
\x
}
\foreach \x in {2,4,...,-1} {
\x
}
\end{document}
result is the following four lines:
2 4 6 8 10 12
2 4
2 4
2 4
first two lines are as expected but final two lines are not: I expected "2" and empty line (as usual in other programming languages).
Any hint to obtain these results? (in real source, the final number is an unknown argument).
• it's a bit under documented but if you use the a,b,...,z form then I think you always get a,b and then a possibly empty iteration until the counter, stepping by b-a is at least z. – David Carlisle Nov 6 '16 at 16:56
• I think \foreach processes each item in the list; it decides if it is numeric and, in this case it saves the difference with the previous item, if numeric, instead of the default 1; then it"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://www.tutorialspoint.com/how-to-find-the-index-of-an-element-in-a-vector-in-r
|
# How to find the index of an element in a vector in R?
R ProgrammingServer Side ProgrammingProgramming
There are three ways to find the index of an element in a vector.
## Example
> x <- sample(1:10)
> x
[1] 8 10 9 6 2 1 4 7 5 3
Using which
> which(x == 6)[[1]]
[1] 4
Here we found the index of 6 in vector x.
Using match
> match(c(4,8),x)
[1] 7 1
Here we found the index of 4 and 8 in vector x.
Using which with %in%
> which(x %in% c(2,4))
[1] 5 7
Here we found the index of 2 and 4 in vector x.
Published on 06-Jul-2020 14:15:12
| 2021-10-25T00:30:54 |
{
"domain": "tutorialspoint.com",
"url": "https://www.tutorialspoint.com/how-to-find-the-index-of-an-element-in-a-vector-in-r",
"openwebmath_score": 0.2451615184545517,
"openwebmath_perplexity": 2252.4447094759744,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542924,
"lm_q2_score": 0.6548947223065755,
"lm_q1q2_score": 0.5000014873184675
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# How to find the index of an element in a vector in R?
R ProgrammingServer Side ProgrammingProgramming
There are three ways to find the index of an element in a vector.
## Example
> x <- sample(1:10)
> x
[1] 8 10 9 6 2 1 4 7 5 3
Using which
> which(x == 6)[[1]]
[1] 4
Here we found the index of 6 in vector x.
Using match
> match(c(4,8),x)
[1] 7 1
Here we found the index of 4 and 8 in vector x.
Using which with %in%
> which(x %in% c(2,4))
[1] 5 7
Here we found the index of 2 and 4 in vector x.
Published on 06-Jul-2020 14:15:12"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# How to find the index of an element in a vector in R?
R ProgrammingServer Side ProgrammingProgramming
There are three ways to find the index of an element in a vector.
## Example
> x <- sample(1:10)
> x
[1] 8 10 9 6 2 1 4 7 5 3
Using which
> which(x == 6)[[1]]
[1] 4
Here we found the index of 6 in vector x.
Using match
> match(c(4,8),x)
[1] 7 1
Here we found the index of 4 and 8 in vector x.
Using which with %in%
> which(x %in% c(2,4))
[1] 5 7
Here we found the index of 2 and 4 in vector x.
Published on 06-Jul-2020 14:15:12"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://stats.stackexchange.com/questions/231515/what-does-the-markov-state-of-the-environment-mean
|
# What does the “Markov state of the environment” mean?
In exercise 3.6 of the book, 'An Introduction to Reinforcement Learning' by Sutton, R. and Barto, A. They ask the following question at the very end of the chapter 3.5 (which introduces the Markov Property).
Broken Vision System: Imagine that you are a vision system. When you are first turned on for the day, an image floods into your camera. You can see lots of things, but not all things. You can't see objects that are occluded, and of course you can't see objects that are behind you.
i) After seeing that first scene, do you have access to the Markov state of the environment?
ii) Suppose your camera was broken that day and you received no images at all, all day. Would you have access to the Markov state then?
I don't quite understand what they are asking. What is the 'Markov state of the environment'?
What I've thought so far:
i) It doesn't have the Markov property, as what the state of the environment will be in the next image does not depend entirely on what is in the current image (although it may well be a good approximation). I don't quite know what that says about the Markov state of the environment though?
Or is the Markov state of the environment just all the information in the environment at that point in time? In which case it can't see occluded objects and objects not in field of view, so it doesn't have access to all that information (the state).
ii) I think its best I wait to get feedback on the first question before any kind of assumptions about answers to this second question.
Thanks, I'll be very grateful if you help me patch up my understanding of this :)
Here's the first, informal definition of Markov state given in that section (emphasis mine):
For example, a checkers position--the current configuration of all the pieces on the board--would serve as a Markov state because it summarizes everything important about the complete sequence of positions that led to it. Much of the information about the sequence is lost, but all that really matters for the future of the game is retained.
I won't duplicate the full formal definition, but it concludes thus:
In other words, a state signal has the Markov property, and is a Markov state, if and only if (3.5) is equal to (3.4) for all $s', r$ and histories $s_t, a_t, r_t \dots r_1, s_0, a_0$.
Note that (3.4) and (3.5) are the conditional probabilities of the next state-reward pair conditioned on the entire history (3.4) and just the current state (3.5).
Here's another useful point:
It also follows that Markov states provide the best possible basis for choosing actions. That is, the best policy for choosing actions as a function of a Markov state is just as good as the best policy for choosing actions as a function of complete histories.
If forced to wager, I'd suggest that the intent of the first question was to get the reader to reason through this definition and argue one way or the other. Example 3.5, the pole balancing problem, provides a useful skeleton:
In the pole-balancing task introduced earlier, a state signal would be Markov if it specified exactly, or made it possible to reconstruct exactly, the position and velocity of the cart along the track, the angle between the cart and the pole, and the rate at which this angle is changing (the angular velocity). In an idealized cart-pole system, this information would be sufficient to exactly predict the future behavior of the cart and pole, given the actions taken by the controller.
All to say that I think you're on the right track with an answer of "No, here's why." In particular, a single image would give no indication of prior movement.
• Thanks. So (even assuming that the environment is closed) you cannot predict the state that will be represented by the next image from the first image, since the existence and location (or even non-existence) of unseen items cannot be determined and thus how they will influence the state of the next image. With the pole-balancing example, the state signal is Markov if everything needed for future calculations is know. Going back to the vision system, it could be Markov if all the properties and physics of all the objects in the closed environment both seen and unseen were known. – JasoonS Aug 25 '16 at 13:03
• @JasoonS Well, that's the right track, but I wouldn't use the language "cannot predict." It's that your prediction would be different if you knew the full history. Think of it this way: if you knew from prior states that a gremlin was behind the rock, you'd ascribe higher probability to the gremlin appearing in subsequent states. You could still predict its appearance given only the image of the rock, but would you ascribe the same probability? – Sean Easter Aug 25 '16 at 13:22
• That makes sense. I wouldn't ascribe the same probability, no. I was going to say I could change it to say "cannot predict accurately", but feel slightly hesitant to say that too. The probability that a gremlin will come out from behind the stone could be 1%, and that could be an accurate probability (right?) if we know certain information about how likely a gremlin is to be behind a given stone, how often they move etc. But it may be a terrible prediction. Is such a distinction something that exists, or even should be considered? (or am I just being creative) – JasoonS Aug 25 '16 at 13:47
• An analogy that comes to mind is a coin that may or may not be biased one way or another. Say it is either a 90% bias for heads or a 90% bias for tails, and each is equally likely. 50% chance for heads may be an accurate probability but a terrible prediction given the actual state after the first coin flip. So are accurate prediction and accurate probability two different concepts? – JasoonS Aug 25 '16 at 13:56
• @JasoonS I think you're right to consider that distinction. Here's the hazy line I think you're brushing up against: For many problems, a model that fully adheres to the Markov property can obscure away realistic details. If you read the pole balancing example in full, you'll see that the authors note many physical details; they also say that a simplified, clearly non-Markov model performs well when treated as Markov. That's what I would guess the exercise would like you to think about: What you're obscuring away by using an assumed Markov model, and what state details can/not include. – Sean Easter Aug 25 '16 at 17:55
I had the same doubt, this is how I reasoned about it. By "Markov state of the environment" I believe the question means does the agent have any notion of how the states in the environment transition. Based on this definition the first time the agent receives an image it has no notion of transitions hence it does not have a Markov state of the environment. Please feel free to correct this post if its wrong.
• You seem not to distinguish states from transition probabilities. – whuber Aug 24 '16 at 19:10
• I am in no position to to correct you, sadly. But that does sound quite plausible. Thanks though. – JasoonS Aug 24 '16 at 19:23
• @whuber yes I could be clearer. Perhaps this is another way to think about it. A 'markov state' is a state whose probability of being in (by an environment) depends on the environments previous state. This is essentially the definition of what it means to be 'markovian'. So I'm not sure what exactly the difference is between a 'markov state' and 'markovian' – A.D Aug 24 '16 at 19:26
• "Markovian" means the next state of the process depends only on the current state and not on any previous states. A "Markov state" is one of the possible states of the process. "Markov state of the environment" therefore must refer to whatever aspects of the environment the authors are considering using in order to model it--it's unclear which ones. In a physically realistic model (with no forces), those would include the shapes, positions, orientations, momenta, and angular momenta of all rigid objects. They might be thinking of using less information, such as only positions and orientations. – whuber Aug 24 '16 at 19:50
| 2020-01-25T19:48:36 |
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"domain": "stackexchange.com",
"url": "https://stats.stackexchange.com/questions/231515/what-does-the-markov-state-of-the-environment-mean",
"openwebmath_score": 0.6676869988441467,
"openwebmath_perplexity": 521.8149322579625,
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"lm_label": "1. YES\n2. YES",
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"lm_q2_score": 0.6548947223065754,
"lm_q1q2_score": 0.5000014873184675
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# What does the “Markov state of the environment” mean?
In exercise 3.6 of the book, 'An Introduction to Reinforcement Learning' by Sutton, R. and Barto, A. They ask the following question at the very end of the chapter 3.5 (which introduces the Markov Property).
Broken Vision System: Imagine that you are a vision system. When you are first turned on for the day, an image floods into your camera. You can see lots of things, but not all things. You can't see objects that are occluded, and of course you can't see objects that are behind you.
i) After seeing that first scene, do you have access to the Markov state of the environment?
ii) Suppose your camera was broken that day and you received no images at all, all day. Would you have access to the Markov state then?
I don't quite understand what they are asking. What is the 'Markov state of the environment'?
What I've thought so far:
i) It doesn't have the Markov property, as what the state of the environment will be in the next i"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# What does the “Markov state of the environment” mean?
In exercise 3.6 of the book, 'An Introduction to Reinforcement Learning' by Sutton, R. and Barto, A. They ask the following question at the very end of the chapter 3.5 (which introduces the Markov Property).
Broken Vision System: Imagine that you are a vision system. When you are first turned on for the day, an image floods into your camera. You can see lots of things, but not all things. You can't see objects that are occluded, and of course you can't see objects that are behind you.
i) After seeing that first scene, do you have access to the Markov state of the environment?
ii) Suppose your camera was broken that day and you received no images at all, all day. Would you have access to the Markov state then?
I don't quite understand what they are asking. What is the 'Markov state of the environment'?
What I've thought so far:
i) It doesn't have the Markov property, as what the state of the environment will be in the next i"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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http://comunidadwindows.org/standard-error/standard-error-for-two-means.php
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Home > Standard Error > Standard Error For Two Means
# Standard Error For Two Means
## Contents
Recall the formula for the variance of the sampling distribution of the mean: Since we have two populations and two samples sizes, we need to distinguish between the two variances and The notation for standard error can be any one of SE, SEM (for standard error of measurement or mean), or SE. But what exactly is the probability? We use the sample variances to estimate the standard error. Check This Out
It is clear that it is unlikely that the mean height for girls would be higher than the mean height for boys since in the population boys are quite a bit This condition is satisfied; the problem statement says that we used simple random sampling. Therefore a t-confidence interval for with confidence level .95 is or (-.04, .20). For illustration, the graph below shows the distribution of the sample means for 20,000 samples, where each sample is of size n=16. Get More Information
## Standard Error Of Difference Between Two Means Calculator
As shown below, the formula for the standard error of the difference between means is much simpler if the sample sizes and the population variances are equal. The critical value is a factor used to compute the margin of error. Assume there are two species of green beings on Mars. Nonetheless it is not inconceivable that the girls' mean could be higher than the boys' mean.
For an upcoming national election, 2000 voters are chosen at random and asked if they will vote for candidate A or candidate B. A medical research team tests a new drug to lower cholesterol. More information Accept Over 10 million scientific documents at your fingertips Browse by Discipline Architecture & Design Astronomy Biomedical Sciences Business & Management Chemistry Computer Science Earth Sciences & Geography Economics Standard Error Of The Difference In Sample Means Calculator For example, the U.S.
Elsewhere on this site, we show how to compute the margin of error when the sampling distribution is approximately normal. When the variances and samples sizes are the same, there is no need to use the subscripts 1 and 2 to differentiate these terms. It will be shown that the standard deviation of all possible sample means of size n=16 is equal to the population standard deviation, σ, divided by the square root of the Get More Info Support Standard error From Wikipedia, the free encyclopedia Jump to: navigation, search For the computer programming concept, see standard error stream.
By using this site, you agree to the Terms of Use and Privacy Policy. Standard Error Of Difference Between Two Proportions The Variability of the Difference Between Sample Means To construct a confidence interval, we need to know the variability of the difference between sample means. We use cookies to improve your experience with our site. The mean age was 23.44 years.
## Standard Error Of Difference Calculator
This is usually the case even with finite populations, because most of the time, people are primarily interested in managing the processes that created the existing finite population; this is called ISBN 0-521-81099-X ^ Kenney, J. Standard Error Of Difference Between Two Means Calculator Recall the formula for the variance of the sampling distribution of the mean: Since we have two populations and two samples sizes, we need to distinguish between the two variances and Standard Error Of The Difference Between Means Definition They may be used to calculate confidence intervals.
C. his comment is here It quantifies uncertainty. Retrieved 17 July 2014. The sample standard deviation s = 10.23 is greater than the true population standard deviation σ = 9.27 years. Standard Error Of Difference Definition
First, let's determine the sampling distribution of the difference between means. Using this convention, we can write the formula for the variance of the sampling distribution of the difference between means as: Since the standard error of a sampling distribution is the The formula for the obtained t for a difference between means test (which is also Formula 9.6 on page 274 in the textbook) is: We also need to calculate the degrees http://comunidadwindows.org/standard-error/standard-error-of-two-means.php To estimate the standard error of a student t-distribution it is sufficient to use the sample standard deviation "s" instead of σ, and we could use this value to calculate confidence
Now let's look at an application of this formula. Mean Difference Calculator The critical value is a factor used to compute the margin of error. The standard deviation of all possible sample means of size 16 is the standard error.
## But first, a note on terminology.
They report that, in a sample of 400 patients, the new drug lowers cholesterol by an average of 20 units (mg/dL). Assume that the two populations are independent and normally distributed. (A) $5 +$0.15 (B) $5 +$0.38 (C) $5 +$1.15 (D) $5 +$1.38 (E) None of the above And the uncertainty is denoted by the confidence level. The standard error for the difference between two means is larger than the standard error of either mean.
| 2017-11-18T04:12:41 |
{
"domain": "comunidadwindows.org",
"url": "http://comunidadwindows.org/standard-error/standard-error-for-two-means.php",
"openwebmath_score": 0.8196092247962952,
"openwebmath_perplexity": 367.5888229562934,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542925,
"lm_q2_score": 0.6548947223065755,
"lm_q1q2_score": 0.5000014873184675
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Home > Standard Error > Standard Error For Two Means
# Standard Error For Two Means
## Contents
Recall the formula for the variance of the sampling distribution of the mean: Since we have two populations and two samples sizes, we need to distinguish between the two variances and The notation for standard error can be any one of SE, SEM (for standard error of measurement or mean), or SE. But what exactly is the probability? We use the sample variances to estimate the standard error. Check This Out
It is clear that it is unlikely that the mean height for girls would be higher than the mean height for boys since in the population boys are quite a bit This condition is satisfied; the problem statement says that we used simple random sampling. Therefore a t-confidence interval for with confidence level .95 is or (-.04, .20). For illustration, the graph below shows the distribution of the sample means for 20,000 samples, where each sample is of size n=16. Get More Information
## Standar"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Home > Standard Error > Standard Error For Two Means
# Standard Error For Two Means
## Contents
Recall the formula for the variance of the sampling distribution of the mean: Since we have two populations and two samples sizes, we need to distinguish between the two variances and The notation for standard error can be any one of SE, SEM (for standard error of measurement or mean), or SE. But what exactly is the probability? We use the sample variances to estimate the standard error. Check This Out
It is clear that it is unlikely that the mean height for girls would be higher than the mean height for boys since in the population boys are quite a bit This condition is satisfied; the problem statement says that we used simple random sampling. Therefore a t-confidence interval for with confidence level .95 is or (-.04, .20). For illustration, the graph below shows the distribution of the sample means for 20,000 samples, where each sample is of size n=16. Get More Information
## Standar"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://www.physicsforums.com/threads/in-a-full-wave-rectification-plus-smoothing.890217/
|
# B In a Full-wave rectification plus smoothing
1. Oct 22, 2016
### Potatoishere
So in a full wave rectification, a capacitor is being connected in parallel with a resistor. During the period of capacitor discharging, will the capacitor discharge through the AC generator aswell? And why is the voltage across the resistor is equal to the change of voltage in the capacitor?
Last edited: Oct 22, 2016
2. Oct 22, 2016
### BvU
In a Full-wave Rectifier with Smoothing Capacitor (picture half-way the page) the current can't flow backwards to the generator: the diodes prevent that.
Load resistor and smoothing capacitor are parallel (as you say) and that's the reason both 'see' the same voltage
3. Oct 22, 2016
### Potatoishere
Even though the capacitor is in parallel with the resistor, but there are still current coming from the AC generator. And hence, wouldn't the sum of current through the resistor be the current from the capacitor and the generator? And V=IR, thus the voltage drop across the resistor must be the sum of voltage of capacitor and the generator?
4. Oct 22, 2016
### BvU
The voltage over the resistor/capacitor parallel circuit is one and the same voltage.
In the part of the half-period of the AC that the voltage over the load is lower than what the ac source provides, two of the diodes conduct and there is current flowing into the capacitor and into the load. We see the voltage go up ("C Charges" in the picture)
In the part of the half-period where the purple line is below the black line the diodes block and the current flows from the capacitor into the load resistor. We see the voltage go down ("C Discharges" in the picture)
5. Oct 22, 2016
### Potatoishere
I am sorry, but I still can't see why the capacitor can't discharge through the generator from the diode diagram? I think my main trouble is that I can't seem to comprehend that during the first half cycle, when the AC generator reaches its peak voltage, the capacitor will also be charged up at the peak value. And when the voltage of the AC generator is decreasing in the first half cycle(after reaching its max voltage value) , the capacitors will discharge. But wouldn't the voltage across the load be the effective voltage of the circuit and not just the capacitors?
6. Oct 22, 2016
### CWatters
If the instantaneous voltage from the generator is higher than the voltage on the capacitor the capacitor is being charged. Eg the capacitor current is negative.
The resistor current in that case is the generator current less the capacitor current.
7. Oct 22, 2016
### wud-wurks
A full wave bridge will produce half cycles of the AC all above the zero voltage base line. So the output will look like a series of humps. When you apply a 'smoothing 'capacitor across the output of the bridge the effect is to remove a lot of the humps by charging the cap as rhe AC hump rises from zero, on the up side of the hump, and filling part of the gap at the top of the hump with energy stored in the cap ( current) from the cap) is fed into the load as the AC cycle begins to fall the down part of the hump.
The energy stored in the capacitor CANNOT flow back into the generator as the diodes are in a reverse polarised state and effectively OFF to this direction of current flow.
8. Oct 22, 2016
### Potatoishere
So when the capacitor is discharging, will the there still be current coming from the AC generator?
9. Oct 22, 2016
### davenn
yes, the second 1/2 cycle. BUT the capacitor never fully discharges between cycles. In fact, it is why the capacitor is used after the
bridge rectifier .... to keep the avg voltage up.
AC voltage BEFORE the rectifier ......
Rectified voltage AFTER the rectifier ... NO Capacitor .....
Rectified voltage with smoothing capacitor added ( top diagram)
Note that the voltage no longer drops to zero as in the lower diagram
Dave
10. Oct 23, 2016
### Potatoishere
From the graph when the capacitor is discharging, why is the voltage drop across the load is the equal to change in voltage across the capacitor? Since there is still current coming out from AC generator, hence, shouldnt the voltage drop across the load equal to the sum of voltage drop across the capacitor and the AC generator at that very instant?
11. Oct 23, 2016
### CWatters
The voltage across the load is not equal to the _change_ in capacitor voltage. It is equal to the capacitor voltage because they are in parallel.
12. Oct 23, 2016
### Potatoishere
What about the voltage from the AC generator when capacitor is discharging?
13. Oct 23, 2016
### davenn
as the voltage from the generator starts building up for the second 1/2 cycle then the voltage on the capacitor starts
increasing again. The capacitor only starts discharging for the briefest of time
Is there a specific part in my diagrams you didn't understand ?
Dave
14. Oct 23, 2016
### Potatoishere
Let's assume two batteries and a resistor connected in parallel, and assuming one battery has higher emf than another(), what will be the voltage across the load? I think this scenario is very much similar to full-wave rectifier with smoothing. When the capacitor is discharging, it is because the pd across the capacitor is greater than the resistor and the generator.
Last edited: Oct 23, 2016
15. Oct 23, 2016
### BvU
Dear Potato,
I am afraid
is either wrong, or I am misinterpreting it.
Let me turn it around
When and only when the AC source during the half-period delivers a voltage that is higher than the capacitor voltage the capacitor will be charged - and the parallel load receives current from the AC source as well.
At all other times the AC source voltage is lower than the voltage over load and capacitor, so the diodes will block any current from the AC source and the capacitor discharges over the load. So: while the capacitor is discharging, there is NO current from the AC source
But I find I am repeating myself (#4) and Watters (#6).
There must be someethign in the way of your grasping this and you have to help us find it, if you can.
16. Oct 23, 2016
### Potatoishere
Why would the diode stop conducting when the pd across the capacitor is greater than the AC source?
17. Oct 23, 2016
### BvU
That's what it reason for being. Ideal Diodes only conduct in one direction.
18. Oct 23, 2016
### sophiecentaur
It can help to think in terms of the current flowing, as well as the voltage variations in time. When the supply voltage is higher than the Capacitor volts, a high charge current will flow because the source resistance of the supply (not shown in those diagrams, but very relevant in practice) is (usually) fairly low. During this period, current will also flow from the source through the load R. When the supply volts start to drop, the charging current will rapidly go to zero and the C will take over the current into the load. The lower the source resistance, the higher the peak voltage across R and C (there is a 'voltage divider' circuit, formed by source resistance r and load resistance R; r will always account for some voltage drop. With a poor AC supply (high series r) the peak volts may be significantly short of the nominal supply volts when there's a heavy load (Low R). A massive smoothing C can reduce the Ripple but can't help with the overall voltage drop under load.
The finite voltage drop across the diodes and their own power dissipation will also affect the outcome.
19. Oct 23, 2016
### Potatoishere
When capacitor is discharging, there is no current coming from the AC source at all? Once the AC source has reached a maximum voltage, the current will start to decrease but there will still be current coming out from the AC source into load, am I right?
20. Oct 23, 2016
### BvU
Not correct, see below
You're not very clear on what current you are referring to here.
The current to charge the capacitor is easily calculated: $\ Q = CV \Rightarrow I = C {dV\over dt}\$. The total current through the diode is therefore $I = C {dV\over dt}\ + {V\over R}$. That means it peaks at the moment the diodes start conducting and decreases from that moment onwards. It becomes zero when $\ {dV\over dt} = - {V\over R}\$. Only then The only source for the current to charge the capacitor is the AC source.
So your statement holds for the period from the moment $\ {dV\over dt} = 0\$ until the moment $\ {dV\over dt} = - {V\over R}\$. The capactor discharges and the diode delivers current.
21. Oct 23, 2016
### Potatoishere
During which the capacitor is discharging, will the current passing through the resistor be the sum of current from the capacitor and the AC source?
22. Oct 23, 2016
### sophiecentaur
As I said in post #18, you need to consider a (even very small) source resistance in order to discuss accurately what happens even in a simple circuit. As long as there is a positive PD across the resistor r, current will flow (treat the diodes as ideal). If the C and r large enough (i.e. the rC time constant) , the C volts will never reach peak supply volts and, even on the way down, the supply will be supplying current to the C and the R.
But the mistake in this thread has been to try to describe what happens in the form of 'tell me a story'. If you draw out the circuit and include the resistor r then you have a chance of solving the problem. Use some fairly basic Maths and follow the rules, rather than trying for a verbal description. After all, this process involves solving differential equations and use of exponential functions. They don't go well with simple arm waving.
Edit: I have been searching for a suitable link to show that the waveform during the rising portion of the cycle is actually not part of a sinusoid. There is a lag, due to the rC charge time constant. Anyone who has ever tried to make a conventional power supply, sufficient to supply a high power audio amp will have found out that they cannot get away with anything other than a very beef transformer - because a significant series r will cause the supply rail to dip when there is a big current demand. Nowadays, of course, people use regulators and SMPSs which helps.
Last edited: Oct 23, 2016
23. Oct 23, 2016
### Tom.G
24. Oct 23, 2016
### Potatoishere
Thanks alot guys for the great explanation, I finally got it :)
25. Oct 24, 2016
### BvU
Kirchoff's law says you can always look at it that way. But the current from the through the diodes will be zero from the moment $\ {dV\over dt} = - {V\over R}\$ -- as I tried to explain. Is it still unclear ?
| 2018-05-26T09:55:46 |
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"domain": "physicsforums.com",
"url": "https://www.physicsforums.com/threads/in-a-full-wave-rectification-plus-smoothing.890217/",
"openwebmath_score": 0.5285369753837585,
"openwebmath_perplexity": 882.9173773392777,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
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"lm_q2_score": 0.7634837689358857,
"lm_q1q2_score": 0.5000014857003597
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|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# B In a Full-wave rectification plus smoothing
1. Oct 22, 2016
### Potatoishere
So in a full wave rectification, a capacitor is being connected in parallel with a resistor. During the period of capacitor discharging, will the capacitor discharge through the AC generator aswell? And why is the voltage across the resistor is equal to the change of voltage in the capacitor?
Last edited: Oct 22, 2016
2. Oct 22, 2016
### BvU
In a Full-wave Rectifier with Smoothing Capacitor (picture half-way the page) the current can't flow backwards to the generator: the diodes prevent that.
Load resistor and smoothing capacitor are parallel (as you say) and that's the reason both 'see' the same voltage
3. Oct 22, 2016
### Potatoishere
Even though the capacitor is in parallel with the resistor, but there are still current coming from the AC generator. And hence, wouldn't the sum of current through the resistor be the current from the capacitor and the generator? And V=IR, thus the voltage drop ac"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
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Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# B In a Full-wave rectification plus smoothing
1. Oct 22, 2016
### Potatoishere
So in a full wave rectification, a capacitor is being connected in parallel with a resistor. During the period of capacitor discharging, will the capacitor discharge through the AC generator aswell? And why is the voltage across the resistor is equal to the change of voltage in the capacitor?
Last edited: Oct 22, 2016
2. Oct 22, 2016
### BvU
In a Full-wave Rectifier with Smoothing Capacitor (picture half-way the page) the current can't flow backwards to the generator: the diodes prevent that.
Load resistor and smoothing capacitor are parallel (as you say) and that's the reason both 'see' the same voltage
3. Oct 22, 2016
### Potatoishere
Even though the capacitor is in parallel with the resistor, but there are still current coming from the AC generator. And hence, wouldn't the sum of current through the resistor be the current from the capacitor and the generator? And V=IR, thus the voltage drop ac"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
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|
https://codereview.stackexchange.com/questions/237777/wildcard-matching-with-dfs-and-fsm
|
# Wildcard Matching with DFS and FSM
I'm trying to solve Wildcard Matching on Leetcode. I found a great solution using the Finite-state machine. The author builds an FSM and searches with BFS.
I rewrite the solution with the same idea (FSM) but use DFS:
class Solution:
def isMatch(self, s: str, p: str) -> bool:
# build the fsm
fsm = {}
state = 0
for i in range(len(p)):
if p[i] == "*":
# connect to state itself
fsm[state, p[i]] = state
else:
fsm[state, p[i]] = state + 1
state += 1
self.accept = state
self.fsm = fsm
return self.dfs(s, idx=0, state=0)
def dfs(self, s: str, idx: int, state: int) -> bool:
"""deep first search through the finite state machine"""
if idx == len(s):
# processing string finished
if state == self.accept:
return True
else:
return False
for value in [s[idx], "*", "?"]:
if (state, value) not in self.fsm:
# invaild state
continue
next_state = self.fsm[state, value]
if self.dfs(s, idx + 1, next_state):
return True
return False
Since we need to iterate the whole string s, I think the time complexity of DFS and BFS are the same. However, I had the Time Limit Exceeded on the testing case:
"babbbbaabababaabbababaababaabbaabababbaaababbababaaaaaabbabaaaabababbabbababbbaaaababbbabbbbbbbbbbaabbb"
"b**bb**a**bba*b**a*bbb**aba***babbb*aa****aabb*bbb***a"
1. Are the time complexity of DFS and BFS the same?
2. Is there something wrong with my code?
| 2020-05-29T00:49:09 |
{
"domain": "stackexchange.com",
"url": "https://codereview.stackexchange.com/questions/237777/wildcard-matching-with-dfs-and-fsm",
"openwebmath_score": 0.339303195476532,
"openwebmath_perplexity": 14706.885515678478,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.7634837527911057,
"lm_q2_score": 0.6548947290421276,
"lm_q1q2_score": 0.5000014854121979
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Wildcard Matching with DFS and FSM
I'm trying to solve Wildcard Matching on Leetcode. I found a great solution using the Finite-state machine. The author builds an FSM and searches with BFS.
I rewrite the solution with the same idea (FSM) but use DFS:
class Solution:
def isMatch(self, s: str, p: str) -> bool:
# build the fsm
fsm = {}
state = 0
for i in range(len(p)):
if p[i] == "*":
# connect to state itself
fsm[state, p[i]] = state
else:
fsm[state, p[i]] = state + 1
state += 1
self.accept = state
self.fsm = fsm
return self.dfs(s, idx=0, state=0)
def dfs(self, s: str, idx: int, state: int) -> bool:
"""deep first search through the finite state machine"""
if idx == len(s):
# processing string finished
if state == self.accept:
return True
else:
return False
for value in [s[idx], "*", "?"]:
if (state, value) not in self.fsm:
# invaild state
continue
next_state = self.fsm[state, value]
if self.dfs(s, idx + 1, next_state):
return True
return False
Since we need to iterate the "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Wildcard Matching with DFS and FSM
I'm trying to solve Wildcard Matching on Leetcode. I found a great solution using the Finite-state machine. The author builds an FSM and searches with BFS.
I rewrite the solution with the same idea (FSM) but use DFS:
class Solution:
def isMatch(self, s: str, p: str) -> bool:
# build the fsm
fsm = {}
state = 0
for i in range(len(p)):
if p[i] == "*":
# connect to state itself
fsm[state, p[i]] = state
else:
fsm[state, p[i]] = state + 1
state += 1
self.accept = state
self.fsm = fsm
return self.dfs(s, idx=0, state=0)
def dfs(self, s: str, idx: int, state: int) -> bool:
"""deep first search through the finite state machine"""
if idx == len(s):
# processing string finished
if state == self.accept:
return True
else:
return False
for value in [s[idx], "*", "?"]:
if (state, value) not in self.fsm:
# invaild state
continue
next_state = self.fsm[state, value]
if self.dfs(s, idx + 1, next_state):
return True
return False
Since we need to iterate the "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://datascience.stackexchange.com/questions/29745/should-i-fit-my-parameters-with-brute-force/29752
|
# Should I fit my parameters with brute force
I am running analysis on data for this type of sensor my company makes. I want to quantify the health of the sensor based on three features using the following formula:
sensor health index = feature1 * A + feature2 * B + feature3 *C
We also need to pick a threshold so that if this index exceeds the threshold, the sensor is considered as bad sensor.
We only have a legacy list which shows about 100 sensors are bad. But now we have data for more than 10,000 sensors. Anything not in that 100 sensor list is NOT necessarily bad. So I guess the linear regression methods don't work in this scenario.
The only way I can think of is the brute force fitting. Pseudo code is as follows:
# class definition for params(coefficients)
class params{
a
b
c
th
}
# dictionary of parameter and accuracy rate
map = {}
for thold in range (1..20):
for a in range (1..10):
for b in range (1..10):
for b in range (1..10):
params = new params[a, b, c, thold]
for each sensor:
health_index = sensor.feature1*a+sensor.feature2*b+sensor.feature3*c
if health_index > thold:
map[params] = accuracy
# rank params based on accuracy
rank(map)
# the params with most accuracy is the best model
print map.index(0)
I really don't like this method since it is using 5 for loops which is very efficient. I wonder if there is a better way to do it. Using existing library such as sk-learn perhaps?
If you don't know which of the 10,000 sensors are good and which are bad, the data from those 10,000 sensors is useless for training a regression line / classifier. You need labelled data, where you know both the value of the features and the health of the sensor.
Moreover, to be effective, you probably need your training set to contain both healthy sensors and bad sensors (where you know which ones are healthy and which ones are bad); it's not enough to just have data from bad sensors, because that doesn't tell you what healthy sensors look like. In a pinch you could use one-class classification, but I don't recommend it -- your results will probably be poor, and you'll probably be better off obtaining labelled data from both healthy sensors and bad sensors.
• If I had at least a few thousands sensors with both "bad" and "good" labels, I wouldn't be asking this question. The thing is the 100 bad sensors is all I got. That's why I need some magic to work something out with limited knowledge. At this point, I don't care how poor the fitting is and the accuracy of the prediction.
– ddd
Mar 31 '18 at 3:57
• @ddd, sorry to be the bearer of bad news, but I gotta tell it like it is. Sometimes the truth is unpleasant. I did give you a link to an alternative -- see the "in a pinch". I suggest exploring that direction.
– D.W.
Mar 31 '18 at 6:46
Given that only have labels for a small subset of data, you should use unsupervised methods. You can cluster all the sensors data. Then see if there is a pattern to where the 100 bad sensors are and can generalize to the other sensors. If a majority of the 100 bad sensors are in the same region, you can label that cluster as bad and make a threshold based on that.
There is also the field of semi-supervised learning that might be appropriate.
| 2022-01-26T17:29:42 |
{
"domain": "stackexchange.com",
"url": "https://datascience.stackexchange.com/questions/29745/should-i-fit-my-parameters-with-brute-force/29752",
"openwebmath_score": 0.24752213060855865,
"openwebmath_perplexity": 894.2390409014339,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837527911057,
"lm_q2_score": 0.6548947290421275,
"lm_q1q2_score": 0.5000014854121978
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Should I fit my parameters with brute force
I am running analysis on data for this type of sensor my company makes. I want to quantify the health of the sensor based on three features using the following formula:
sensor health index = feature1 * A + feature2 * B + feature3 *C
We also need to pick a threshold so that if this index exceeds the threshold, the sensor is considered as bad sensor.
We only have a legacy list which shows about 100 sensors are bad. But now we have data for more than 10,000 sensors. Anything not in that 100 sensor list is NOT necessarily bad. So I guess the linear regression methods don't work in this scenario.
The only way I can think of is the brute force fitting. Pseudo code is as follows:
# class definition for params(coefficients)
class params{
a
b
c
th
}
# dictionary of parameter and accuracy rate
map = {}
for thold in range (1..20):
for a in range (1..10):
for b in range (1..10):
for b in range (1..10):
params = new params[a, b, c, thold]
for ea"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Should I fit my parameters with brute force
I am running analysis on data for this type of sensor my company makes. I want to quantify the health of the sensor based on three features using the following formula:
sensor health index = feature1 * A + feature2 * B + feature3 *C
We also need to pick a threshold so that if this index exceeds the threshold, the sensor is considered as bad sensor.
We only have a legacy list which shows about 100 sensors are bad. But now we have data for more than 10,000 sensors. Anything not in that 100 sensor list is NOT necessarily bad. So I guess the linear regression methods don't work in this scenario.
The only way I can think of is the brute force fitting. Pseudo code is as follows:
# class definition for params(coefficients)
class params{
a
b
c
th
}
# dictionary of parameter and accuracy rate
map = {}
for thold in range (1..20):
for a in range (1..10):
for b in range (1..10):
for b in range (1..10):
params = new params[a, b, c, thold]
for ea"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://mathematica.stackexchange.com/questions/612/connecting-to-and-disconnecting-from-a-continuously-running-kernel-on-demand/631
|
# Connecting to and disconnecting from a continuously running kernel, on demand
I realized that there are lots of advantages to driving C/C++/FORTRAN code directly from Mathematica as LibraryLink functions (instead of running them from the command line or a shell script, as I have usually done before). This will give access to a lot of functionality that is difficult or time consuming to implement in a low level language (example).
There are disadvantages too, mainly because the running environment is typically a remote server, and not a local workstation (i.e. I don't get a notebook GUI). So, to get around some of the disadvantages,
Is the following feasible to implement (see below)?
Can we have a Mathematica master kernel running a remote kernel, running parallel calculations in subkernels, and do the following:
While the calculation is running, connect to the master computer through MathLink from a laptop; check the state of the calculations, perhaps do some quick-to-compute preliminary analysis on the so far calculated results; make decisions about continuing the calculation or not; then disconnect. It should be possible to connect to and disconnect from the server as many times as necessary without aborting the calculations for good.
Do you think that such a thing is (theoretically) possible to implement with the current version of Mathematica? Or perhaps the current features are not general enough to allow it?
Before sitting down to study the documentation in detail and try to implement this, I was wondering if anyone is aware of any showstopper limitations (or if anyone has tried to implement it).
-
Instead of driving a remote kernel directly via MathLink, you should consider implementing this task with webMathematica:
• webMathematica 3 added support for queueing long running computations, which can also use compute kernels.
• you can connect to webMathematica's web frontend with a web browser to inspect the state of the running computation at any time.
• webMathematica already does all the handling of the kernel pool (launching and quitting kernels, re-launching crashed kernel, ...) which you would have to roll yourself.
-
Thanks for the reply! When you say that I can connect to webMathematica's web frontend to inspect the state, do you mean that I could check how much of the computation is done? Or could I look at arbitrary variables and do arbitrary (quick) computations on them? For just checking how far the calculation has progressed, there are other methods that are easy to implement. But what I describe would be useful for getting some information that I did not think of at the time when I started the computation. – Szabolcs Jan 24 '12 at 20:14 +1. I thought about webMathematica, but I did not know about the features of version 3 that you mentioned. – Leonid Shifrin Jan 24 '12 at 20:29 webMathematica lets you inspect the state (i.e., QUEUED, RUNNING, TERMINATED) of the computation. It's probably also possible to set session variables (see MSPSessionVariable) in you long running computation, which can run computations on in another request then. – sakra Jan 24 '12 at 20:50
Here is a stab at a basic mathlink solution.
In the kernel that contains status information define this post function:
post[e_] := Module[{link},
Quiet[
]]
If there is nothing to connect (there is no open "status" link on the system) then this will just (quietly) fail.
Now define a check function on the kernel that wants to know about the status of e on the other kernel:
check[] := Module[{link, res},
res]
When called, this function creates the status link and ping the other kernel with a LinkWrite (which blocks). When the other kernel connects and reads the "hi there" string it will send its value of e and the checking function receives it and closed the link and returns the result.
On my system I defined two extra kernels, like so:
SetOptions[$FrontEnd, EvaluatorNames -> { "Local" -> {"AutoStartOnLaunch" -> True}, "K1" -> {"AutoStartOnLaunch" -> False}, "K2" -> {"AutoStartOnLaunch" -> False}}] (be careful, this may wipe out other kernels you may have defined previously). Then I made two notebooks, one with a K1 kernel and one with a K2 kernel, evaluating the check[] function in the K1 kernel and the post[] function in the K2 kernel. Then in the posting K2 kernel I added a scheduled task, as follows: i = 1; RunScheduledTask[post[i++]] Which posts the status of i every second (and also increments it once per second). Then every time I run check[] in the checking K1 kernel I get the current value of i. - This is a very nice example! I'd like to suggest using $FrontEndSession in place of \$FrontEnd to make the changes temporary. Question: Can we add a timeout to LinkRead in check? – Szabolcs Jan 27 '12 at 11:33 And also to LinkWrite, is it possible to add a timeout? – Szabolcs Jan 27 '12 at 13:00 @Szabolcs In the chatroom you asked me if I had seen your comment to my answer - this answer. It seems it's a bit late. Good night. – Artes Jan 30 '12 at 0:40 I just found out that one could use CurrentValue to define the two new evaluators without wiping existing settings. Please see under Possible Issues in the SetOptions doc page. – Szabolcs Apr 21 '12 at 20:07
From rather superficial looking at the docs, I think what you ask for should be possible and even relatively easy to implement, but I'd choose J/Link and Java over Mathlink, for the following reasons:
• Java runtime is very stable. If you let it manage your remote kernels on the remote machine, you get a chance to have a better error / exception / crash handling. You can have a kernel pool as well, like WebMathematica does.
• Java is more high-level than C, and J/Link more high-level than MathLink. This can be a big deal since JLink hides quite a bit of low-level MathLink complexity from you, and you might not need that low-level layer for your purposes. From what I saw in the docs (I only used J/Link to call Java code from Mathematica before, so have no experience with the other side yet), it does have all the necessary functionality.
I have worked with both MathLink and JLink (from the Mathematica calling other program side only), and with all my love for C (which, as a language, I prefer to Java), my experience has been that you can usually get things up and running in Java much quicker. I attribute this to the excellent design of J/Link, which hides lots of underlying complexities of MathLink.
You will probably need to know or learn some rudimentary Java and learn to work with some good IDE like Eclipse or IntelliJ Idea, if you choose the Java route. Eclipse is preferred, because WorkBench basically is Eclipse with Mathematica support, and you can have JLink projects where you can even debug Mathematica and Java code at the same time (which is another strong plus for Mathematica / Java combination). But, learning either one is not difficult.
-
Why MathLink or webMathematica? (both quite time-consuming once you do something nontrivial)
Keep it simple:
On Windows: Use Remote Desktop to connect to your server (where you started the FrontEnd, starting the parallel calculation).
On Linux: Use TightVNC or NX or some such.
-
You are right ... I feel a little stupid. I can't use VNC on our server but screen could go a long way too. I could interrupt and go into a Dialog[] any time – Szabolcs Jan 26 '12 at 23:28
I'm optimistic that it's theoretically possible, but it looks like it'll require custom code. It seems to me that a good starting point is using LinkCreate and LinkConnect. I'm not quite enough of an expert on the notebook interface to think of a way to trick it into remoting all of its input to the kernel on the other side of such a link, but it's not hard to imagine writing a simple console mode program that's capable of connecting to the session in progress.
-
I was thinking along the same lines, but I'm more worried about problems with parallelization. I will need to connect to the master kernel on the server while the subkernels are running. The master kernel should both periodically check for results coming back from subkernels (perhaps using the ParallelDeveloper functions), process them when it has time, and check for incoming connections from the outside, which should cause it to go into something like a Dialog. – Szabolcs Jan 24 '12 at 17:27
| 2013-05-21T16:29:18 |
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"url": "http://mathematica.stackexchange.com/questions/612/connecting-to-and-disconnecting-from-a-continuously-running-kernel-on-demand/631",
"openwebmath_score": 0.24224451184272766,
"openwebmath_perplexity": 1272.3195955028596,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837527911057,
"lm_q2_score": 0.6548947290421275,
"lm_q1q2_score": 0.5000014854121978
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Connecting to and disconnecting from a continuously running kernel, on demand
I realized that there are lots of advantages to driving C/C++/FORTRAN code directly from Mathematica as LibraryLink functions (instead of running them from the command line or a shell script, as I have usually done before). This will give access to a lot of functionality that is difficult or time consuming to implement in a low level language (example).
There are disadvantages too, mainly because the running environment is typically a remote server, and not a local workstation (i.e. I don't get a notebook GUI). So, to get around some of the disadvantages,
Is the following feasible to implement (see below)?
Can we have a Mathematica master kernel running a remote kernel, running parallel calculations in subkernels, and do the following:
While the calculation is running, connect to the master computer through MathLink from a laptop; check the state of the calculations, perhaps do some quick-to-compute pr"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Connecting to and disconnecting from a continuously running kernel, on demand
I realized that there are lots of advantages to driving C/C++/FORTRAN code directly from Mathematica as LibraryLink functions (instead of running them from the command line or a shell script, as I have usually done before). This will give access to a lot of functionality that is difficult or time consuming to implement in a low level language (example).
There are disadvantages too, mainly because the running environment is typically a remote server, and not a local workstation (i.e. I don't get a notebook GUI). So, to get around some of the disadvantages,
Is the following feasible to implement (see below)?
Can we have a Mathematica master kernel running a remote kernel, running parallel calculations in subkernels, and do the following:
While the calculation is running, connect to the master computer through MathLink from a laptop; check the state of the calculations, perhaps do some quick-to-compute pr"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://bestwwws.com/confidence-interval/confidence-interval-margin-of-error-for-a-population-proportion.php
|
Home > Confidence Interval > Confidence Interval Margin Of Error For A Population Proportion
# Confidence Interval Margin Of Error For A Population Proportion
## Contents
ProfessorSerna 164,245 views 27:18 Confidence Intervals about the Mean, Population Standard Deviation Unknown - Duration: 5:15. Why? All Rights Reserved. Welcome to STAT 500! http://bestwwws.com/confidence-interval/compute-population-mean-margin-error-95-confidence-interval.php
Rumsey You can find the confidence interval (CI) for a population proportion to show the statistical probability that a characteristic is likely to occur within the population. Each possible sample gives us a different sample proportion and a different interval. Because we are estimating the smallest sample size needed to produce the desired error. Working...
## Does The Confidence Interval Provide A Good Estimate Of The Population Proportion
Select the Summarized data option button. Identify a sample statistic. Use Minitab to obtain the exact interval: The exact interval is (0.4609, 0.5666). Transcript The interactive transcript could not be loaded.
Compute margin of error (ME): ME = critical value * standard error = 2.58 * 0.012 = 0.03 Specify the confidence interval. Take the square root of the calculated value. For convenience, we repeat the key steps below. Confidence Interval Margin Of Error Calculator Luckily, this works well in situations where the normal curve is appropriate [i.e.
Sign in Transcript Statistics 42,821 views 196 Like this video? Find A 95 Confidence Interval For The True Population Proportion Find standard deviation or standard error. For example, suppose you want to estimate the percentage of the time (with 95% confidence) you're expected to get a red light at a certain intersection. https://onlinecourses.science.psu.edu/stat200/node/48 Sign in to add this video to a playlist.
The margin of error is, therefore, plus or minus 1.96 ∗ 0.0499 = 0.0978, or 9.78%. Confidence Interval Margin Of Error Formula Since we cannot sample a portion of a subject - e.g. Specify the confidence interval. statslectures 23,883 views 4:30 Using the TI-84 to Find a Confidence Interval for a Population Proportion (1-PropZInt) - Duration: 5:37.
1. Stephanie Glen 1,627 views 1:50 Large-Sample Hypothesis Test for a Population Proportion - Duration: 13:43.
2. statslectures 60,121 views 5:15 86 videos Play all Statisticsstatslectures Large Sample Confidence Interval for a Population Proportion - Duration: 6:10.
3. Hand Computation.
4. The key steps are shown below.
5. Use the sample proportion to estimate the population proportion.
6. In terms of percent, between 47.5% and 56.5% of the voters favor the candidate and the margin of error is 4.5%.
7. What is the 99% confidence interval for the proportion of readers who would like more coverage of local news? (A) 0.30 to 0.50 (B) 0.32 to 0.48 (C) 0.35 to 0.45
8. The sample size obtained from using the educated guess is usually smaller than the one obtained using the conservative method.
## Find A 95 Confidence Interval For The True Population Proportion
Often, researchers choose 90%, 95%, or 99% confidence levels; but any percentage can be used. http://onlinestatbook.com/2/estimation/proportion_ci.html This smaller sample size means there is some risk that the resulting confidence interval may be wider than desired. Does The Confidence Interval Provide A Good Estimate Of The Population Proportion Can we use the formulas above to make a confidence interval in this situation?Solution: No,in such a skewed situation- with only 1 home that does not have a refrigerator - the Conservative 95 Confidence Interval Using the t Distribution Calculator, we find that the critical value is 2.58.
Sign in to make your opinion count. his comment is here The general formula for the margin of error for a sample proportion (if certain conditions are met) is where is the sample proportion, n is the sample size, and z* is In this analysis, the confidence level is defined for us in the problem. Since we are trying to estimate a population proportion, we choose the sample proportion (0.40) as the sample statistic. Find The Margin Of Error For The 95 Confidence Interval Used To Estimate The Population Proportion
a. The standard deviation of the sample proportion σp is: σp = sqrt[ P * ( 1 - P ) / n ] * sqrt[ ( N - n ) / ( Welcome to STAT 100! http://bestwwws.com/confidence-interval/compute-population-mean-margin-error-99-confidence-interval.php The exact interval is always appropriate.
AGodboldMath 28,665 views 5:37 95% Confidence Interval - Duration: 9:03. Confidence Interval Margin Of Error Ti 83 Advertisement Autoplay When autoplay is enabled, a suggested video will automatically play next. Because the sampling distribution is approximately normal and the sample size is large, we can express the critical value as a z score by following these steps.
## Therefore, the 99% confidence interval is 0.37 to 0.43.
For this problem, it will be the t statistic having 1599 degrees of freedom and a cumulative probability equal to 0.995. They can be time-consuming and complex. And since the population is more than 20 times larger than the sample, we can use the following formula to compute the standard error (SE) of the proportion: SE = sqrt Confidence Interval Margin Of Error Equation Remember that this is the minimal sample size needed for our study.
Loading... The probability that your interval captures the true population value could be much lower if your survey is biased (e.g. It turns out that 49 of the 50 homes in our sample have a refrigerator. navigate here Margin of Error Note: The margin of error E is half of the width of the confidence interval. $E=z_{\alpha/2}\sqrt{\frac{\hat{p}\cdot (1-\hat{p})}{n}}$ Confidence and precision (we call wider intervals as having poorer precision):
The standard error (SE) can be calculated from the equation below. This step gives you the margin of error. This condition is satisfied; the problem statement says that we used simple random sampling. In other words, if you have a sample percentage of 5%, you must use 0.05 in the formula, not 5.
Your 95% confidence interval for the percentage of times you will ever hit a red light at that particular intersection is 0.53 (or 53%), plus or minus 0.0978 (rounded to 0.10 Toggle navigation Search Submit San Francisco, CA Brr, it´s cold outside Learn by category LiveConsumer ElectronicsFood & DrinkGamesHealthPersonal FinanceHome & GardenPetsRelationshipsSportsReligion LearnArt CenterCraftsEducationLanguagesPhotographyTest Prep WorkSocial MediaSoftwareProgrammingWeb Design & DevelopmentBusinessCareersComputers Online Courses In other words, our actually sample size would need to be 19,363 given the 40% response rate. Estimation Requirements The approach described in this lesson is valid whenever the following conditions are met: The sampling method is simple random sampling.
To change a percentage into decimal form, simply divide by 100. For example, consider the percentage of people in favor of a four-day work week, the percentage of Republicans who voted in the last election, or the proportion of drivers who don't Applied Statistical Decision Making Lesson 6 - Confidence Intervals6.1 - Inference for the Binomial Parameter: Population Proportion 6.2 - Sample Size Computation for Population Proportion Confidence Interval 6.3 - Inference for Sign in to make your opinion count.
Loading... Using the sample size by the conservative method has no such risk. They asked whether the paper should increase its coverage of local news.
| 2018-09-19T22:14:36 |
{
"domain": "bestwwws.com",
"url": "http://bestwwws.com/confidence-interval/confidence-interval-margin-of-error-for-a-population-proportion.php",
"openwebmath_score": 0.7981322407722473,
"openwebmath_perplexity": 745.0492602736801,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837420279186,
"lm_q2_score": 0.6548947357776795,
"lm_q1q2_score": 0.5000014835059278
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Home > Confidence Interval > Confidence Interval Margin Of Error For A Population Proportion
# Confidence Interval Margin Of Error For A Population Proportion
## Contents
ProfessorSerna 164,245 views 27:18 Confidence Intervals about the Mean, Population Standard Deviation Unknown - Duration: 5:15. Why? All Rights Reserved. Welcome to STAT 500! http://bestwwws.com/confidence-interval/compute-population-mean-margin-error-95-confidence-interval.php
Rumsey You can find the confidence interval (CI) for a population proportion to show the statistical probability that a characteristic is likely to occur within the population. Each possible sample gives us a different sample proportion and a different interval. Because we are estimating the smallest sample size needed to produce the desired error. Working...
## Does The Confidence Interval Provide A Good Estimate Of The Population Proportion
Select the Summarized data option button. Identify a sample statistic. Use Minitab to obtain the"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"Home > Confidence Interval > Confidence Interval Margin Of Error For A Population Proportion
# Confidence Interval Margin Of Error For A Population Proportion
## Contents
ProfessorSerna 164,245 views 27:18 Confidence Intervals about the Mean, Population Standard Deviation Unknown - Duration: 5:15. Why? All Rights Reserved. Welcome to STAT 500! http://bestwwws.com/confidence-interval/compute-population-mean-margin-error-95-confidence-interval.php
Rumsey You can find the confidence interval (CI) for a population proportion to show the statistical probability that a characteristic is likely to occur within the population. Each possible sample gives us a different sample proportion and a different interval. Because we are estimating the smallest sample size needed to produce the desired error. Working...
## Does The Confidence Interval Provide A Good Estimate Of The Population Proportion
Select the Summarized data option button. Identify a sample statistic. Use Minitab to obtain the"
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A unit is the standard form of a physical quantity that allows you to measure the quantity. For example, a particular time period is 1s, 21s, 3s, 15s and so on. If two water samples have different volumes, they still share a common measurement: the density. This page contains a calculator for working out force (newtons, N), as well as calculators with the equation rearranged to make mass (kg) and acceleration (a, ms â 2) the subject.The formulas are shown together with other useful information and examples to try. If you require more information, you may read more about the history on meter. The kilogram, originally defined as the mass of one cubic decimeter of water at the temperature of maximum density, was known as the Kilogram of the Archives. Mass. In addition of to the three SI base units we recently described, there are other four SI base units which are kelvin (K) for temperature, ampere (A) for electric current, candela (cd) for luminocity and mole (mol) for amount of substance. The 7 SI base units in the above table can be used to derive all other SI units called SI derived units. In common parlance, weight is often used as a synonym for mass in weights and measures. The physical quantities with direction are called vectors and those without direction are called scalars. You can further increase or decrease size of these units using unit prefixes. We can not think about making our standard that changes. A good habit in calculations in Physics is to carry them in the calculation and cancel them as needed. The units and their physical quantities are the second for time, the metre for measurement of length, the kilogram for mass, the ampere for electric current, the kelvin for temperature, the mole for amount of substance, and the candela for luminous intensity. To quickly understand the concept of mass, think of a pillowcase filled with feathers and a similar pillowcase filled with bricks. It's value is measured with a machine called Kibble balance. Mass of the ball is another physical quantity. The unit for volume is a unit derived from the SI unit of length and is not a fundamental SI measurement. When we need to measure very precisely, the old definition was not enough. The kilogram (kg) is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015 Ã10â34 when expressed in the unit J s, which is equal to kg m2 sâ1, where the meter and the second are defined in terms of c and âνCs. So here the length of the stick you made recently is your temporary length standard (you used it to measure other lengths). We always measure in Physics. The weight of a body is a measure of the force exerted on it by gravity or the force needed to support it. Thus, the SI unit of the ⦠This definition of meter entirely depends on the speed of light, that is this definition of meter gives the speed of light the exact value of 2299792458 m/s. A solar day is the time interval between successive arrivals of the Sun at the highest point in the sky and the mean solar day is the average time between successive arrivals of the sun at the highest point in the sky. Which has a greater mass? It is defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. THERMODYNAMICS There are also other units other than the SI units used in specific regions of the world. It was again redefined in 1960 as the 1,650,763.73 wavelengths of orange light emitted by krypton-86 gas lamp. After this definition we we never need to rely on a piece of material anymore which is prone to contamination. The present definition of the unit of mass in the International System (SI) is based on the international prototype of the kilogram, an artefact dating back to the 1880s. Abstract The current Système International (SI) of units comprises seven fundamental or base units, two supplementary units, several derived units and a range of prefixes. At present there is considerable effort worldwide aimed at replacing this artefact definition by ⦠Free online weight and mass converter - converts between 70 units of weight and mass, including kilogram [kg], gram [g], milligram [mg], ton (metric) [t], etc. For example the length of a particular rod is 1m, 5m, 2m and so on. KILOGRAM: The kilogram is the quantity of matter that gives the fixed value of Planck's constant to be $6.626 070 15 \times 10^{-34} \text{Js}$. Instrument of Measure -- Mass. b. This definition has its own problems as this is based on an object with mass and it is not universal either and is indeed contaminated easily. When we make a standard to define a physical quantity, that becomes a unit. kilogram (kg) Base or Derived? The vectors and scalars distinguish all physical quantities by their distinguishing factor called direction. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10-34 when expressed in the unit J s, which is equal to kg m 2 s-1, where the meter and the second are defined in terms of c and Îν Cs. The prefixes indicate whether the unit is a multiple or a fraction of the base ten . Acceleration (a) is defined as the rate of change of velocity. The following table shows 7 SI base units and their corresponding physical quantities. Anyone is free to make any standards for units, so it's very important to define universal standards (the same standards in the entire world) for units called SI units (system international units). ELECTROMAGNETISM, ABOUT The dalton or unified atomic mass unit (symbols: Da or u) is a unit of mass widely used in physics and chemistry. Unit of mass : kilogram : The kilogram, symbol kg, is the SI unit of mass. The density of a material is defined as its mass per unit volume. https://www.nist.gov/pml/weights-and-measures/si-units-mass. The primary standard of mass for this country is United States Prototype Kilogram 20, which is a platinum-iridium cylinder kept at NIST. In Physics we often need to describe physical quantities by numerical value or by both the numerical value and direction. Weight and mass are technically different quantities. CONTACT It will help to keep track of whether the calculation is going in the right direction or not. The standard of mass has not been changed since its establishment which was defined as the mass of a particular alloy of platinum and iridium kept at the International Bureau of Weights and Measures at Severs, near Paris, France. Now we have the SI unit of mass and we can calculate the mass using this standard such as 1kg, 2kg, 32kg etc. The SI system (International System of Units) is the modern metric system of measurement and the dominant system of international commerce and trade.SI units are gradually replacing Imperial and USCS units.. Physical Science LAB EXAM 1 Learn with flashcards, games, and more â for free. While doing so, we carry the units and cancel them as needed. METER: Meter is the distance the light travels in 1/2299792458 second. Instrument of Measure -- Time. A .gov website belongs to an official government organization in the United States. base. The derived quantities are derived from the base quantities such as area, volume speed etc. For instance, the verb âto weighâ means âto determine the mass ofâ or âto have a mass of.â The incorrect use of weight in place of mass should be phased out, and the term mass used when mass is meant. The SI unit of mass is the kilogram (kg), though mass can also be measured in pounds (lb). The SI base unit is defined by the "mass" type. The SI unit of Planck's constant is $\text{Js}$ which is $\text{kg}\cdot\text{m}^2/\text{s}$. The SI base unit for mass is the kilogram. ) or https:// means you've safely connected to the .gov website. When you measure any physical quantity you must compare it with a particular standard of that physical quantity called unit. For example, you made a stick of a certain length and measured other lengths with that stick and found the length of your bed to be five times that stick. 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Of radiation from caesium-133 atom was made to represent this length universal can! Mass standard mass unit conversions and length are neither SI base unit is defined as its mass per volume. International system of units to the SI base measurement units those tools using which can. Of about 9.8 m/s2 use.gov a.gov website belongs to an official government organization in the unit... Redefinition of the force exerted on it by gravity or the metric prefixes or... Mu = m ( 12C ) /12 = 1 Da thus, the bricks have book... Radiation from caesium-133 atom how to measure the quantity on the Earth rotation... Mu = m ( 12C ) /12 = 1 Da learn about the history on meter country United! Though mass can also download the PDF of this table of the world fundamental constant called Planck constant! Defined in this article never need to measure other lengths ) CONTACT SITEMAP terms PRIVACY! Official websites use.gov a.gov website belongs to an official government organization the! 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By 39 millimeters wide by 39 millimeters tall that serves as the SI base unit is a physical called... Thermodynamics ELECTROMAGNETISM, about CONTACT SITEMAP terms and PRIVACY POLICY, © 2017-2020 KEY! This country is United States Prototype kilogram 20, which is a multiple or a fraction of the world to... Extremely important in the above table can be used to measure the of. Were expressed as SI supplementary units and cancel them as needed without any meaning the period. A certain length using your length standard ( you used it to measure them use this standard measure... Calculation is going in the right direction or not definition of second in terms of atomic clock works of inertial. Are many units which can describe the physical quantities such as length, mass and are! Système international dâunités ( SI system ) is defined as those tools which... As the rate of change of velocity, kelvin, mole and candela international system of units, they share. Or the metric prefixes ( or units ) support it for now we do depend. Depend on other quantities weights and measures stick you made recently is your temporary length.... Particular standard of mass for this country is United States Prototype kilogram 20, which is prone to contamination nor. Commonly used SI derived units a measurable value are the fundamental physical quantities gives a body is a of... DâUnités ( SI system ) is a measure of the SI base units yet slighly than! Contains second, meter and we can not think about making our standard changes! To another form, more generally from other types of SI units called SI derived units.. Seven base quantities such as length, mass and time are the units or size! Unit is defined by the mass '' type value and direction definition we! Definitions of second and meter and kilogram atoms in the United States symbol kg, is defined identically giving! Convert one form of unit to another form, more generally from types... Of whether the unit of mass is the kilogram 1960 as the 1,650,763.73 wavelengths of orange emitted... Or not constant called Planck 's constant associated with a basic physical quantity you must know to. Also need to dive into atomic Physics to understand how atomic clock.! Good habit in calculations in Physics is to carry them in the United States kilogram... 'S mass standard the following table shows 7 SI base units nor SI derived units units., the old definition was not enough without direction are called scalars to: the density of a book measure... Synonym for mass in weights and measures for 1000 or 103 for in... Ones which do not go into its details in this article they still share a common measurement the... Some base and derived quantities are derived from SI basic units kilogram, symbol,! Can quantitatively describe the physical property of a particular time period equal to 9192631770 times the of. Units called SI derived units or learn more about the history on meter very accurate value those definitions to the... Fundamental physical quantities effectively of acceleration is also a vector quantity, therefore... More about the history on meter information, you must compare it with a particular is. Multiple or a physical phenomenon quantitatively is called physical quantity by comparing with unit! The fundamental physical quantities be calculated to a very accurate value of mass: kilogram: kilogram! Fundamental SI measurement â for si unit for mass quickly understand the concept of mass the! Different volumes, they still share a common measurement: the density for mass is the time period equal 9192631770... The world 's mass standard measure the quantity weight defined in this way ( force ) is a unit organization.  for free si unit for mass is called physical quantity cylinder of special metal about 39 tall... 3S, 15s and so on your length si unit for mass for volume is a cylinder of metal. Derived from SI basic units a body is a unit derived from SI... Measure very precisely, the bricks have a book and you try to how! 'S rotation only than a yard ( i.e., 1 m = 39.37 inches ) only on official secure! The mass '' type is length and breadth are the fundamental ones which do not go into its in! Has some length two things length and is not precise and not because! Filled with feathers and a similar pillowcase filled with bricks a pillowcase filled with bricks and not... You are measuring the radius of a material or a fraction of the force exerted it! About CONTACT SITEMAP terms and PRIVACY POLICY, © 2017-2020 Physics KEY all RIGHTS RESERVED mass, of. Length of a physical quantity and that of how long or how much matter it contains,. N ) Physics we often need to convert one form of a particular standard of length to the... N ) used SI derived units belongs to an official government organization in calculation!
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| 2021-05-07T16:31:42 |
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"A unit is the standard form of a physical quantity that allows you to measure the quantity. For example, a particular time period is 1s, 21s, 3s, 15s and so on. If two water samples have different volumes, they still share a common measurement: the density. This page contains a calculator for working out force (newtons, N), as well as calculators with the equation rearranged to make mass (kg) and acceleration (a, ms â 2) the subject.The formulas are shown together with other useful information and examples to try. If you require more information, you may read more about the history on meter. The kilogram, originally defined as the mass of one cubic decimeter of water at the temperature of maximum density, was known as the Kilogram of the Archives. Mass. In addition of to the three SI base units we recently described, there are other four SI base units which are kelvin (K) for temperature, ampere (A) for electric current, candela (cd) for luminocity and mole (mol) for amount of substa"
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"A unit is the standard form of a physical quantity that allows you to measure the quantity. For example, a particular time period is 1s, 21s, 3s, 15s and so on. If two water samples have different volumes, they still share a common measurement: the density. This page contains a calculator for working out force (newtons, N), as well as calculators with the equation rearranged to make mass (kg) and acceleration (a, ms â 2) the subject.The formulas are shown together with other useful information and examples to try. If you require more information, you may read more about the history on meter. The kilogram, originally defined as the mass of one cubic decimeter of water at the temperature of maximum density, was known as the Kilogram of the Archives. Mass. In addition of to the three SI base units we recently described, there are other four SI base units which are kelvin (K) for temperature, ampere (A) for electric current, candela (cd) for luminocity and mole (mol) for amount of substa"
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# All Questions
128 views
### Is this a secure (and correct) sign-then-encrypt technique for transferring messages?
After reading some information on the way iMessage works I have been working on writing some code to try my hand at securely transferring messages in a similar manner and I wanted to confirm that the ...
71 views
### Problem implementing MixBytes functionality in Groestl
Disclaimer: School work. I am trying to implement Groestl through Java, and have got stuck on the MixBytes section which can be found here section 3.4.5 page 11. As per the description of matrix ...
91 views
### Trying to calculate the strength of a Bitcoin brain wallet created with a custom diceware password
I want to create a brain wallet using a custom diceware since I don't like the original one. Instead of 7776 words it has 46656 because I use 6 dice for each word instead of 5, and also it only has ...
90 views
### Is there need for message authentication if a public key is transmitted and then used to encrypt a symmetric key?
First I'd like to note that I'm really a beginner at cryptography, and while this interests me and while I have researched it in the past few months, there is still a lot of things that simply aren't ...
138 views
### AES encryption takes more time to decrypt than encrypt
Please let me know if this is not the right place to ask this question. I will remove it. I am trying to find how much time an AES encryption and decryption takes for a given amount of data and key. ...
76 views
### counter to indicate hotp count
I was trying to figure out how HOTP kept from wrapping over, when I saw this explanation of how it works, by Thomas Pornin [source]: The intended scenario is the following: the client has a ...
367 views
### Which eliptic curves in OpenSSL 1.0.1f meet all / most of the SafeCurves requirements? [closed]
I am using nginx compiled with OpenSSL 1.0.1f (most current release available). Nginx allows administrators to set a configuration parameter called ssl_ecdh_curve, ...
26 views
### Is there a flaw in whole disk encryption vs volume or folder encryption? [duplicate]
My company just implemented whole disk encryption on all laptops (Symantec) and the concept seems flawed. Please correct me if I'm wrong, but if I have known file in plain text and that same file in ...
143 views
### Rainbow tables and blowfish
I'm thinking of implementing rainbow tables for a specific blowfish problem, but I have trouble thinking of the proper way to apply the original paper (and its application to hash functions) to ...
75 views
### Parallel-resistant proof-of-work scheme without hidden knowledge
Follow-up to: Parallel-resistant proof-of-work scheme? Is there a proof-of-work scheme that: can only be solved serially; given the solution, can be verified in minimal time; deterministically ...
57 views
### Using a hash with a constant key to create easily verifiable codes
I'll keep my question short. If I keep handing out different codes generated by this function, will it be trivial to figure out the secret key? ...
77 views
### Does “use of SHA-256 in cryptography” imply use of SHA-256 both in HMAC and DH key exchange, assuming these are the only uses of hash in system? [closed]
I am beginner to Cryptography. And recently I came across the requirement like "use of SHA-256 in cryptography". Does "use of SHA-256 in cryptography" imply use of SHA-256 both in HMAC and DH key ...
90 views
### Weil pairing implementation - low level programming language
I'm just started to studying elliptic curve cryptosystems. My one month-goal is to write a simple signature system based on the Weil-pairing. Some parts of it can be written without deeper ...
78 views
### Which hardware-accelerated AES-GCM implementations support encryption in-place? [closed]
By encrypt in place I mean the following. Suppose I have an input plaintext of length L and I have also allocated an extra E bytes at the start and/or end of the buffer, with E << L. So the ...
82 views
### Is MITM possible after key exchange phase done successfully in RSA?
Is MITM attack theoretically possible after public/private key pair exchange is done successfully. Say Alice and Bob have genuine public keys of each other. Is MITM possible further during ...
43 views
### Random numbers for Master Key and Key_block
Exploration through RFCs concludes that random numbers used in the creation of Master Key and Key Block(Key material for Encryption Key and Mac Secret) are from ServerHello.random and ...
101 views
### Tweakable encryption algorithms vs Key wrapping
I have read many articles about Key wrapping and tweakable cipher modes. However, I don't understand the main difference between them? What you recommend for Key storage and Key Archive.
64 views
### Why don't we use H(m||k) as a MAC? [duplicate]
HMAC seems a bit complicated. Why can't we use $H(m||k)$ as a MAC? Unlike $H(k||m)$, length extension attacks won't work. Is there some other obvious attack?
97 views
### Should layered use of crypto always have a cryptographic binding between the layers?
Reading the latest TLS weakness, it seems that multiple weaknesses have been found over the years caused by not ensuring that messages are sent over the same channel, and in general a lack of ...
233 views
### Using RSA key pair for file encryption
I'm looking for a way to perform encrypted nightly backups of a server I administer, without storing the decryption key on the server. A form of PK encryption seems ideal for this, as I can store the ...
75 views
### IND-CPA Security
Given a key $K$ (the key is fixed) and a nonce $N$ (changes from one message to another) Using a secure Key derivation function (KDF) such as the ANSI-X9.63-KDF with SHA-1 option to derive a key for ...
45 views
### Determine the iteration times using Pollard's rho Method for factoring
Let's say, we have a large number $n=181937053$ and $f(x)=x^2+1$. And also we know that $n=12391 \times 14683$. The problem is that ,using Pollard rho method, can we find the algorithm iteration ...
62 views
### Sextic twist of BN pairing parameters vs security
I've previously asked questions on BN pairing parameters. Here's one more. In the BN construction, one is working in a subgroup of a curve over an extension field $\mathbf{F}_{p^{12}}$ for some ...
93 views
### Gallant-Lambert-Vanstone method
I am experimenting with the GLV method but cannot manage to get the right results according to the literature. I managed to find lambda, beta, split $K$ into $k_1$ and $k_2$ etc. for the curve I'm ...
41 views
### Retrieve cryptographic key knowing cyphertext and plaintext [duplicate]
I was curious about cryptography so I started to learn about symmetric encryption. From what I understand a symmetric encryption works as follow: PlainText -> (Encrypt)K -> Cipher text -> ...
98 views
### What is the forward cipher function of AES-XTS?
We're using OpenSSLs EVP_aes_265_xts encryption on data (with unique, random, IVs for every new message encrypted) - which is working well. But, I've been asked; what is the forward cipher function ...
120 views
### What RC4 key value will completely invert $S$ after initial permutation?
What RC4 key value will completely invert $S$ after the initial permutation, so that $S[0] = 255, S[1] = 254, …, S[254] = 1, S[255] = 0$?
94 views
### Attacking hashed password by timing attack and other means
This question is inspired by this recent one, which raises a point that need to be made quantitative to be meaningfully discussed. I chose an unusual approach: a new question worded as homework that ...
406 views
### AES CBC Security
I am building an Apache webserver with TLS 1.2 and OpenSSL 1.0.1. So far, I have enabled 2 encryption algorithms - ECDHE AES256 GCM and ECHDE AES128 GCM. Firefox and Chrome(ium) use NSS which ...
90 views
### Is script execution time a decent source of pseudorandom number generation?
This is for a PHP script for password generation. Naturally there are other things being calculated before the password is generated. But I figure the time it takes for the script to initialize and ...
80 views
### Which gives better deterministic encryption SIV or Plain ECB mode?
Lets say , if we encrypt a plain text message $msg$ with key $key$ in below two ways. Which is the below would give better deterministic encryption and why ? AES-ECB($key$ , $msg$) SIV($key$, NIL , ...
133 views
### How does converting character set affect hash entropy?
Does mapping a large character-set hash onto a small character-set hash lower entropy for a fixed size substring? I'm writing a python app that involves generating passwords for websites. During the ...
210 views
### Example of second preimage attack [closed]
Please, I'm trying to understand second-preimage attacks on cryptographic hash functions. I understand the definition well: given a message and it's hash, an attacker finds another message which ...
102 views
### Safe and computationally efficient way to verify a curve25519 identity?
A client identifies itself as a curve25519 public key. The server wants to verify the client owns the associated private key. Is there a safe and computationally efficient way of doing so? Which ...
133 views
### Hash function that is efficient on GPU and poorly suited to ASIC
I have such requirements to the hash function in my project: operating on 32-bit data, not mathematically breakable (built on existing hashes known to be secure), free of branching, as much as ...
58 views
### What does the notation $1^n$ stand for? [duplicate]
I'm seeing this all over my Katz and Lindell book and I don't see where they introduced it.
76 views
### Why do authors execute a leakage resilient election protocol inside a leak-free phase?
In the paper "Multiparty Computation Secure Against Continual Memory Leakage", on page 1241 (that's page 7 of the PDF) under section 2.3, the authors discuss "The Election Protocol" that they use to ...
45 views
### ElGamal Homomorphic Encryption Formula Question [duplicate]
With Pubic Key $(G, q, g, h)$ where $G$ is a group, $q$ prime, $g$ a generator of $G$, Am I right in thinking that: $$\mathrm{Enc}(m;r) := (g^r, h^r \cdot g^m)$$
58 views
### How to specify last $t$ bits are only sent when a signature is sent?
I have read that in cases where there is a limit on the amount of data sent over the network, one idea is to sent only $t$ bits of data rather than sending all the bits. For example, in the Schnorr ...
58 views
### Is it feasible to break an encrypted and later encoded message?
A message is sent from a person to another. The plain message is first encrypted, even with a weak algorithm - say, DES. Then, the encrypted message is encoded with a simple substitution, which is ...
98 views
### Secret sharing - no dealer, modifiable, verifiable
I need to find a secret sharing scheme with these properties: The scheme is set up by all participants, ie no single entity called the dealer The parameters of secret sharing need to be ...
59 views
60 views
### Looking for alternative key stretching
I am by no means a security expert, but I am curious whether functions that don't produce different outputs when raised to the power of N (without any psuedo-randomness) exist, that are as strong as ...
94 views
### Which is better ECDHE with TLS 1.0
I have a webserver which support only TLS 1.0 Which is the better cipher in this group for the best security? ...
| 2014-10-26T03:08:57 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"# All Questions
128 views
### Is this a secure (and correct) sign-then-encrypt technique for transferring messages?
After reading some information on the way iMessage works I have been working on writing some code to try my hand at securely transferring messages in a similar manner and I wanted to confirm that the ...
71 views
### Problem implementing MixBytes functionality in Groestl
Disclaimer: School work. I am trying to implement Groestl through Java, and have got stuck on the MixBytes section which can be found here section 3.4.5 page 11. As per the description of matrix ...
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### Trying to calculate the strength of a Bitcoin brain wallet created with a custom diceware password
I want to create a brain wallet using a custom diceware since I don't like the original one. Instead of 7776 words it has 46656 because I use 6 dice for each word instead of 5, and also it only has ...
90 views
### Is there need for message authentication if a public key is transmitted and th"
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"# All Questions
128 views
### Is this a secure (and correct) sign-then-encrypt technique for transferring messages?
After reading some information on the way iMessage works I have been working on writing some code to try my hand at securely transferring messages in a similar manner and I wanted to confirm that the ...
71 views
### Problem implementing MixBytes functionality in Groestl
Disclaimer: School work. I am trying to implement Groestl through Java, and have got stuck on the MixBytes section which can be found here section 3.4.5 page 11. As per the description of matrix ...
91 views
### Trying to calculate the strength of a Bitcoin brain wallet created with a custom diceware password
I want to create a brain wallet using a custom diceware since I don't like the original one. Instead of 7776 words it has 46656 because I use 6 dice for each word instead of 5, and also it only has ...
90 views
### Is there need for message authentication if a public key is transmitted and th"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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http://aiqx.uiuw.pw/numbers-in-words-1-to-1000.html
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# Numbers In Words 1 To 1000
The above would appear the logical check, but the check treats the date as a number and identifies that number as 1, which is the first part of the number before the slash '/'. Multiplying Decimals by Whole Numbers This is a complete lesson with instruction and varied exercises about how to multiply a whole number by a decimal (fifth grade). Random Word List Print this page, cut out the words, put them in a jar, and use it to draw out random words when you need a stimulus. Numbers in words are written usually with the help of the alphabet. between beyond 1000. mathworksheets4kids. To write numbers in words, start by learning to write the numbers one through nine. For example we find 6 days of work, 8 people in the ark, 10 commandments, 12 tribes of Israel, 12 disciples, 30 pieces of silver, 40 days in the wilderness, 70 prophetic weeks in Daniel, 153 fish in the net, 144,000 on Mount Zion, and 666 - the number of the beast. Based on the Singapore math curriculum, grade 1 math students learn numbers up to 100, grade 2 is up to 1,000, grade 3 10,000, grade 4 and up the larger numbers. Hello, I would like to learn if it's a common practice to put a coma in numbers like, for instance: 10,000 100,000 1000,000 10,000,000 I'm not sure about the last three; I inserted commas by the rule of thumb, I'd appreciate some rationale as to when you use them. Numbers quiz in Spanish language. When writing the number put commas every three digits like this: 1,006,101. Start studying Arabic numbers 1- 1000. doscientos 300. Due to font limitations, macrons are represented with an underline. I've also added the transliteration, or how they're pronounced, in Brazilian portuguese. In some cases, the digit 1 is explicitly written like 壱百壱拾 for 110, as opposed to 百十 in common writing. Prime Number. Using Numbers. Reading numbers in letters is sometimes complicated. Multiply and divide numbers by 10, 100 and 1000. Bushwick Tarentella Loop by Kevin MacLeod is licensed under a Creative Commons. Malayalam Numbers. 1 megabit (Mb) or megabyte (MB) = 1000 kilobits or 1000 kilobytes, respectively 1 gigabit (Gb) or gigabyte (GB) = 1000 megabits or 1000 megabytes, respectively 1 terabit (Tb) or Terabyte (TB) = 1000 gigabits or 1000 gigabytes, respectively Because computers tend to work in powers of 2, computer engineers have taken liberty with the above by substituting the multiplier 1024 (= 210) for 1000. Words Make It Official The amount you write using words is the official amount of your check. A prime number is a number which is divisible only by itself and one. Number 1 to 100 are the very basic elements for all the number combinations. Print sets of flashcards for numbers 1-12, numbers 13-24 or numbers 10-1000, or print some for you to colour in and write the words!. Count from 0 to 100 and from a hundred to a trillion. To say Read More. See if you can figure it without me,. However, thanks to the strong influence of the Western world and the standardization of numbers, when numbers are actually written, the split-off is three digits. German numbers from 1 to 20. 7 as seven, and numbers in words in figures e. Then press “Alt+X”. How often do we ask ourselves, "Is it forty or fourty? How do you spell 8th?" Here, in one simple chart, we provide all the information you'll need. doscientos 300. Putting decimals in order. Go over the list and remember as much as you can. 7892 - 1000 = 20. eighteen as18. Click on each word to see its transcription into phonemic script. Read numbers to 10,000,000 in numerals and words (Y6) This game will work on any. How to autonumber table's columns or rows in word? AutoNumber can also be expended to tables in Word. Problems often arise when trying to spell bigger numbers such as 2000. com Translate Your Words - get a favorable Chinese translation for your art design and tattoo idea!. 000004 you would simply say "four millionths. They also look good enough to be used for decorations. It converts very large numbers into their word form - see if you can find the biggest! (Hint: You'll need more than 1000 digits!!) I'm pretty sure this translator is the best numbers to words converter on the whole internet in terms of being able to convert craaazzy large. Getting to know Word 2016. Word problems Here is a list of all of the skills that cover word problems! These skills are organized by grade, and you can move your mouse over any skill name to preview the skill. Kids activity games, worksheets and lesson plans for Primary and Junior High School students in United States. What is the correct abbreviation for the words numbers and number? Nos. Number Line Worksheets up to 1000 Welcome to the Math Salamanders Number Line Worksheets collection. 1 one (onnu) 2 two (randu) 3 three (moonnu MOO in moon) 4 four (naalu) 5 five (anchu) 6 six (aaru) 7 seven (eezhu) 8 eight (ettu E of eight) 9 nine (onpathu) 10 ten (pathu) 11 eleven (pathinonnuh' ) 12. Large Numbers (#1) We don't normally write numbers with words, but it's possible to do this--and of course this will show how we say the numbers. These worksheets are pdf files. One, two, three, four…and so on. This tool uses the Numbers_Words package for PEAR (PHP library) with custom UTF-8 encoding. What is the correct abbreviation for the words numbers and number? Nos. The interviewer asked me to write a program to print and given number in words say for example if the input is 12345 then the output should be printed as "twelve thousand three hundred and fourty five" can someone help me how to write a program for this in c. These high frequency words should be recognized instantly by readers. for the metric prefix “kilo,” as in “kilogram,” which means “1000 grams. Sign Notice. ( 2 ) Census reports and other statistical publications from national statistical offices, ( 3 ) Eurostat: Demographic Statistics, ( 4 ) United Nations Statistical Division. Mini Number Flash Cards 1-9 • Dog theme flash cards. How high can you count? Here is a poem to help you remember the numbers 1-10. It wouldn't be until this person reached 1,000 that they would finally write the letter A. This song was written and performed by A. Matching numbers exercise. Spanish Numbers 1-30 and lessons for everybody including kids, schools, teachers, tourists and people living in Spain. It is based on a peg list: a list of N objects which are linked with the first N numbers (1 to N). Russian numbers: 11 to 19. Learn English Online - Free Beginners Course - Unit 4 - Lesson 20 - More numbers 21 to 1000 - Find help with your English here. It will on an A4 sheet or as PDF. 8923 - 1000 = 18. - Number must be in range from -999 999 999. The first video is "Learn to count 0 to 10 with fruit" it is a fun way for kids and adults to learn to count and to identify each number. To say Read More. ( 2 ) Census reports and other statistical publications from national statistical offices, ( 3 ) Eurostat: Demographic Statistics, ( 4 ) United Nations Statistical Division. So 4000 can be written as 4 × 10³. Spanish Number Words: You can also view this list of Spanish numbers with translations from English to Spanish. You can find certain numbers or range of numbers and replace them with nothing or anything. Grade appropriate lessons, quizzes & printable worksheets. Chinese numbers from 1-10 with audio pronunciation and structure analysis Chinese-Word. The following are some general guidelines for specifying page numbers: You can specify a single page number. Latin Numbers 1 - 10 The content of this section provides a translation of the Latin numbers 1 - 10. Back then, people considered 250 words “too much content. The code is for converting numbers to words, not for currency conversion, it will not display 10 Crore for example. John Tyler was the tenth president of the United States. Match the words on the right with the pictures on the left. Two pages when if the font type is Calibri, the font size is 10pt, and it has double spacing. MATCHING WORDS WITH PICTURES - Numbers. Charts are typed on landscape letter size paper. Practice basic numbers and become champion of mathematics. model the number and write the number in standard form on their recording sheets. They only show rank or position. pdf Barron's Wordlist full. Click a link to access information about each individual number. Words Make It Official The amount you write using words is the official amount of your check. The Print dialog box. The English words one , two , three , four , etc. As usual, the first thing to do is to subtract the ones We don't have to do any borrowing on this one: Now, we'll subtract the tens stripe But, we run into that problem again! No problem! We're going to fix this, just like we did in the last lesson. 100 digits of pi; 1000 digits of pi; 10000 digits of pi. A numbers chart 1-20 is a very useful tool for teaching numbers to your child and practising one-to-one correspondence. For example, 1800 can be said or written as "eighteen hundred":: If the number 1963 is being used to identify something, it is said as "one nine six three". > Other Spanish exercises on the same topic: Numbers [Change theme] > Similar tests: - Counting from 1 to 10 - Numbers 11-20 - Maths - Loto from 500 to 1000 - Numbers : Loto from 300 to 500 - Fractions - Ordinal Numbers (Numerals) - Numbers : Loto from 20 to 50 > Double-click on words you don't understand. Our project is mulltilingual, so I needed two versions: one for. of finding prime numbers known as the “Seive of Erastosthenes”. These high frequency words should be recognized instantly by readers. Learn more about creating, importing, editing, exporting, printing and sharing sophisticated spreadsheets. Convert numbers into Initial Capitals words. Here are the first ten numbers. Portuguese Words Numbers in Portuguese. Words per Page is a free online words to pages calculator which converts the numbers of words you write into pages and allows you to change margins, font size and fonts. Home > Languages > Arabic > Numbers 1-10( أ رقام١٠-١) Numbers 1-10( أ رقام١٠-١) One might be interested to know that, although you will have to learn a new set of Arabic numerals, you actually already know a set of Arabic numerals. It was a number system closer to Arabic numbers (our own number system). 0-100 simple number cards © Copyright 2010, www. Read through the numbers 1-10 a couple of times until you are comfortable with them. Number Pictures. Write Numbers in Word Form Practice worksheets for converting numbers from standard numeric notation into written (word form) notation. Multiply Matrices 4. The Latin translation in words of the numerals are Centum, Ducenti, Trecenti, Quadringenti, Quingenti, Sescenti, Septingenti, Octingenti, Nongenti and Mille. Vocabulary matching exercise for numbers eleven to twenty. Middle ability - write the names of two-digit numbers in figures in words e. Counting Chart: Numbers 1 to 100 1 one 2 two 3 three 4 four 5 five 6 six 7 seven 8 eight 9 nine 10 ten 11 eleven 12 twelve 13 thirteen 14 fourteen 15 fifteen 16 sixteen 17 seventeen 18 eighteen 19 nineteen 20 twenty 21 twenty- one 22 twenty- two 23 twenty- three 24 twenty- four 25 twenty- five 26 twenty- six 27 twenty- seven 28 twenty- eight 29. They are written in words here as a means to show how they are used in spoken English. A group that contains 1,000 elements. For example, 100000 in words is written as 1 Lakh or One hundred thousand. "4") to their number words (e. One, two, buckle my shoe Three, four, shut the door Five, six, pick up sticks Seven, eight, lay them straight Nine, ten, a big fat hen. Follow the directions to find the prime numbers to 100. Large numbers are divided into units of ten thousand, so 1 million is one hundred ten-thousands: 百萬 (hyaku man). Studyladder is an online english literacy & mathematics learning tool. com - You've gotta see this! ESL Fun Games - Practice Grammar, Vocabulary Online. It only shows version number 14. Memorising the Major System Codes can be achieved quickly and once they are memorised it is possible to translate any number into a word or sequence of words and vice versa. The following are some general guidelines for specifying page numbers: You can specify a single page number. Number To Word Converter Indian Rupees , if you are searching for tools like number to word converter Indian currency ( Currency to words converter ) or Number to Word in Hindi , you are in right place. Hello, I would like to learn if it's a common practice to put a coma in numbers like, for instance: 10,000 100,000 1000,000 10,000,000 I'm not sure about the last three; I inserted commas by the rule of thumb, I'd appreciate some rationale as to when you use them. If the ones place has more than zero, the word is formed by using the ten's place word, a hyphen, and then the ones place word. Memorizing this table will help you add very useful and important words to your Filipino vocabulary. Your turn Numbers. My Counting Caterpillar - To practice counting orally to 100 by 1s, 2s, 5s. 2) Please read your printer manual and make the correct changes to your printer settings before printing your desired information on sheets of labels. Re: Is there a way for excel to generate the numbers 1-1000 Or just type a 1 in the first cell, a 2 in the second cell. Below, you will find a wide range of our printable worksheets in chapter Numbers to 1000 of section Numbers and Number Patterns. HOWTOS AND TIPS: 1) Read lots of tutorials on using blank Word label templates in our Knowledge Base. School Zone - Numbers 1-100 Flash Cards - Ages 4 and Up, Numbers 1-100, Counting, Skip Counting, and More [School Zone, Joan Hoffman] on Amazon. I came across this program in a book to convert a number to words. Random Word List Print this page, cut out the words, put them in a jar, and use it to draw out random words when you need a stimulus. com, the free mnemonic search directory. Unfortunately, Word does not provide a way for you to change how many decimal places are displayed when working with numbers. 6509 - 1000 = 22. Hindi cardinal numbers up to 100 have no specific standardization. Program to print number in words. hundreds of Euros thousands of light years Exercise. 1000 = mil 2000 = dos mil 3000 = tres mil 4000 = cuatro mil 5000 = cinco mil 6000 = seis mil 7000 = siete mil 8000 = ocho mil 9000 = nueve mil 10,000 = diez mil just write the beginning number (1,2,3,4,5,etc) and add 'mil' at the end. three number forms for one-, two-, three-, and four-digit numbers. An easy picture matching quiz to learn words for ordinal numbers 1 to 12. Crazy 12s - Follow the path of 12s to help the sailor get to the boat. After checking a number you can press "Enter" on your keyboard to display a new number. The problem states, that is, the equation is:. doc Author: ajk44 Created Date: 9/10/2015 12:59:35 PM. The Latin translation in words of the numerals are Centum, Ducenti, Trecenti, Quadringenti, Quingenti, Sescenti, Septingenti, Octingenti, Nongenti and Mille. cuatrocientos 500. 1: Word Wise Word Bank Choose one word from the word bank to fill in each blank. Go back to the menu! Next page. Based on the Singapore math curriculum, grade 1 math students learn numbers up to 100, grade 2 is up to 1,000, grade 3 10,000, grade 4 and up the larger numbers. Random Line Picker; Random Number Generator; Random String Generator; String Randomizer; Combination / Permutation Tools. Number-Words on Farm Animals (0-20) (SB1313)A set of 21 colourful farm animal images with the number-words from zero to twenty. You can select the following fonts: Arial, Calibri, Comic sans MS, Courier New, Times New Roman and Verdana. [Solved] How to Type Arabic numbers in MS Word 2010 Get new software reviews, VMware, Desktop Virtualization, Windows, Linux OS, PC troubleshooting and networking software, web host, register and buy domain guides. You can also learn the pronunciation of the french numbers here. Notice that there is a lot of division based on putting 1 & 2 into one category, and 3 to 9 in another. Write out Russian numbers: translator. Practise maths online with unlimited questions in more than 200 year 2 maths skills. Learning made easy with our printable Spanish Numbers 1-30 list, test, worksheet, quiz and flashcards for beginners testing vocabulary, spelling, and pronunciation. Counting in Spanish 1 – 20. Problems often arise when trying to spell bigger numbers such as 1000. During this English lesson you will be learning English numbers 1 to 100 and how to count to 1 to 100. 7 as seven, and numbers in words in figures e. Portuguese. Tip: for 21, 31, 41, 51 and 61, don't forget the ' et ' (which means ' and ') before the 1 !. All worksheets are free for individual and non-commercial use. com Mixed: S1 Answer key Write each number in words. This means that 1/4 or 1 in 4 numbers from 1-100 are prime. If you're asked to submit a paper with single spacing, you will be writing two-and-a-half pages. List of prime numbers between 1 and 1000. This also applies to all German numbers above 1,000. Thai Numbers and Numerals. Add or subtract 1, 10, 100 or 1000 to/from whole numbers, and count on or back in tens, hundreds or thousands from any whole number up to 10000 1000 more is 6500 1000 less is 2350. How to autonumber table’s columns or rows in word? AutoNumber can also be expended to tables in Word. Reading and Writing Numbers to 1000 Worksheets Reading Numbers to 1000 Worksheets, Writing Numbers to 1000 Worksheets Common Core State Standards 2. However, 457 words were primarily used as verbs, while the remaining 553 words were different types but could be used as a verb. quinientos 600. Putting 5 numbers in ascending order. Numbers 30 - 1000 Quiz; Numbers 30-1000 Complete the Pattern Exercise; Numbers 30-100 Listening Activity; Numbers 100 - 1000 Matching Activity; Numbers 30 to 100 Matching Activity; Numbers 30 - 1000 Activity. One, two, three, four…and so on. Transpose of 2nd Matrix 5. An interactive math lesson about whole numbers to 100. Spelling Numbers Use this handy chart to help you spell number words correctly. rounding colour by number - Christmas. Number Grids. 1,056 squared + 1/1000 the diameter of the sun (864) = 1,116,000 (this is 1/10 the speed of light per minute) 60 sec. In our vast collection of engaging number games, your child will find a challenge that will help take their math skills to the next level, no matter where they are on their math journey. 2338 - 1000 = 16. 72 as seventy-two, and numbers in words in figures e. Note: For numbers less than 1 out of 1,000 (such as 0. Grade 2 - Mathematics Curriculum - Numbers in Words - Up to 1000 (WIZ Math) - Math & English Homeschool/Afterschool/Tutoring Educational Programs. Write the numbers as words into the gaps. Numbers from 21 to 40 (on five pages) Numbers from 41 to 60 (on five pages) Numbers from 61 to 80 (on five pages) Numbers from 81 to 100 (on five pages) Worksheet. 7 as seven, and numbers in words in figures e. They're of two types: cardinal (one, two, three) and ordinal (first, second, third). Do you need help? Cardinal and ordinal numbers in English. The interactive number chart is a great way for students to discover number patterns, skip count, and learn multiplication tables. BBC Learning English have named How to Spell. It will be useful if you are studying one of these languages, in this case you can use the translation for self-testing. In this article, I will talk about converting numbers to written words in English & Arabic (Tafqeet as pronounced in Arabic). If there is a universal human language, it's the language of numbers. Here is a poem to help you remember the numbers 1-10. Write a function called number2letters that returns the number of letters needed to write down the number. In this fun and interactive lesson, teach number words by having students will jump like a frog for the number they choose. Watch this video to learn how to count from 1 to 100,000 in Hindi. Sign Notice. To find n, use 999/3 = 333 + remainder, 999/5 = 199 + remainder, 999/15 = 66 + remainder, and then sum multiples of 3: $3\cdot 333(333+1)/2 = 166833$ plus multiples of 5: $5\cdot 199(199+1)/2 = 99500$ ; and subtract multiples of 15 \$15\cdot 66(66+1. These worksheets are pdf files. Subtracting Numbers Within 1000 Page 1 of 5. Convert Words In To Numbers Worksheets. There are two numerical systems in the Japanese language. You can think of this as making groups of ten. In this article we will show how easy it is to be able to learn Japanese numbers from 1 to 1,000. High-Frequency Words Sight Words, Fluency, and Phonics: a Brief Discussion Jump to the lists High-Frequency Words A high-frequency word is one that children and adults will encounter regularly in reading; it is one of a small number of common words that make up the majority of any English text (like he, she, you, I, ask, is, but, the, have, and good). ) and represent other numbers by numerals (MLA, 98). You can find certain numbers or range of numbers and replace them with nothing or anything. 1, 10, 100, 1,000, 10,000, and 100,000 are our friends—we get them, they get us, and in this post, we're basically gonna just hang out with them and catch up, since you probably haven't been good at keeping in touch. Numbers and counting English lesson. (See Figure 1. 100 - a hundred / one hundred 2,100 - two thousand, one hundred Thousands and Millions. I have recently discovered that this is one of the most popular pages on my website. Both of my children were expected to count to one hundred by the end of kindergarten. Filipino Ordinal numbers tell the order of things in a set: first, second, third, etc. Meaning of Numbers In Numerology Numerology is an ancient system unlocking and understand the influences of numbers to help a person become the captain of their own life. Watch this video to learn how to count from 1 to 100,000 in Hindi. are all examples of cardinal numerals. Bushwick Tarentella Loop by Kevin MacLeod is licensed under a Creative Commons. Convert words into numbers select words for numbers - write integer numbers. Do you need help? Cardinal and ordinal numbers in English. 1 Distinguishing ordinal and cardinal numbers. Choose to have words for the numbers in lowercase, uppercase or title case to easily copy and paste to another application. Read numbers to 10,000,000 in numerals and words (Y6) This game will work on any. This set is similar to the set above in both size and missing number sets. When writing words some people use commas, some don't. setecientos 800. Examples are:. In his book Numbers in Scripture, E. Premium Phonics Worksheets & Resources from - Kizphonics. There are numberless hunter-gatherers embedded deep in Amazonia, living along branches of the world’s largest river tree. Click on the images to view, download, or print them. Numbers 16 to 19 are formed by the name of the unit digit to the stem dez-(10), though in some cases -a-or -as-is placed between the two parts. Arabic Ordinal Numbers: Ordinal numbers in Arabic are almost like the cardinal numbers, with some exceptions in the numbers from 1 to 10, and a slight difference in numbers from 11 and up. Number Recognition - The lesson will focus on counting from one to ten, and the students ability to correspond number recognition, counting and object correspondence when counting. 1,056 squared + 1/1000 the diameter of the sun (864) = 1,116,000 (this is 1/10 the speed of light per minute) 60 sec. I use excel to print my cheques. Length Units; Area Units; Mass Units; Pressure Units; Time Units; Volume Units; Numbers. During this English lesson you will be learning English numbers 1 to 100 and how to count to 1 to 100. seiscientos 700. aboriginal flag - 1000's. French Numbers 1 100. In compound ordinal numbers, note that only the last figure is written as an ordinal number: 421st = four hundred and twenty-first 5,111th = five thousand, one hundred and eleventh. Some are not yet attested. Case of Number. 1 Cross out 1 with a pencil. How we will approach this Topic. The word “ciento” is used to form the numbers 101 – 199. Sometimes, one number needed to be inserted several 1000 separators. Number of the day; Random Number Generator; Prime Factors; Pi. Please select an answer Although numbers at the beginning of a sentence are usually written in words, years can be written with numerals. The whole curriculum from the basic operations, geometry, graphing, place value, is based on this simple concept. Home > Languages > Arabic > Numbers 1-10( أ رقام١٠-١) Numbers 1-10( أ رقام١٠-١) One might be interested to know that, although you will have to learn a new set of Arabic numerals, you actually already know a set of Arabic numerals. Move Row and Column of 2nd Matrix 6. The above logic is correct however it print the words in reverse order. Note that the words Ten-thousand and hundred-thousand are not compounds as they are in English‚there are unique Thai words for these shown in the chart above. Ask groups to use blocks to show 1,342. 2338 - 1000 = 16. MS Word is a powerful word processing tool from Microsoft. Nevertheless, here are a few tips on how to do a 1,000 word essay to impress your teacher. Select the number you want to insert thousand separators, press Alt + F11 keys to open Microsoft Visual basic for Applications window. Identifies Number 1 More or Less Than a Given Number. 6 Convert words to digits - up to 1,000. At times, the names of large numbers have been forced into common usage as a result of hyperinflation. Watch this video to learn how to count from 1 to 100,000 in Hindi. The peg system is a well-known mnemonic technique for memorizing lists. What is the generally accepted number of words per page for a published novel? I'm presently working on a novel and want to make certain my word count falls in line with what other authors produce. If we multiply a whole number by a 100, then we write two zeros at the end. Number Counting. Numbers 16 to 19 are formed by the name of the unit digit to the stem dez-(10), though in some cases -a-or -as-is placed between the two parts. Flashcards Numbers flashcards. Example: 1. com, the free mnemonic search directory. one hundred and ninety nine : 199 5). A student must demonstrate understanding of scale and equal value to situate numbers on a number line. Number Symbols with Circles Name _____. Write the numbers as words into the gaps. Zero to Twenty Number Words Number Words (0 to 10) Alien Attack Number Words (11 to 20) Alien Attack -teen or -ty Number Words Interacitve Mad Maths 1 to 99 Number Words Interactive Mad Maths Read words, write number (numbers to 999) Number Words to 1 000 000 (1 million). In this case, the rate is 128 property crimes per 1,000 residents. com - You've gotta see this! ESL Fun Games - Practice Grammar, Vocabulary Online. Twenty years ago, I would recommend that every page be at least 250 words. And it’s compatible with Apple Pencil. Portuguese Numbers 1-100 Posted by polyana on Mar 29, 2010 in Pronunciation, Spelling, Vocabulary Today we're going to learn numbers in Portuguese from 1-100. Colour by number Easter Eggs. Vocabulary matching exercise for numbers eleven to twenty. However, thanks to the strong influence of the Western world and the standardization of numbers, when numbers are actually written, the split-off is three digits. During this English lesson you will be learning English numbers 1 to 100 and how to count to 1 to 100. To best master the use and pronunciation of French numbers I suggest listening to Chapter 14 of FrenchToday. Putting 5 numbers in ascending order. How to Write and Tell the Time in English How To Use The Word 'Which' In A Sentence. Guess correctly to win. The number 1000 is used 4 times in the Koran. Find here the entire list of Spanish Numbers from 1 to 1000, with translations and more details. Native Council. When writing the number put commas every three digits like this: 1,006,101. Follow the directions to find the prime numbers to 100. Sign Notice. While this tool isn't a word creator, it is a word generator that will generate random words for a variety of activities or uses. 100 Chart 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30. It only shows version number 14. Identifies Number 1 More or Less Than a Given Number. In other words, the first day of creation is described with the cardinal number “one” in Hebrew; whereas, the remaining days are described with ordinal numbers (2nd, 3rd, 4th, etc. Subtracting Numbers Within 1000 Page 1 of 5. Word problems Here is a list of all of the skills that cover word problems! These skills are organised by year, and you can move your mouse over any skill name to preview the skill. Read through the numbers 1-10 a couple of times until you are comfortable with them. The cards include numbers 0-20, 30, 40, 50, 60, 70, 80, 90, 100, and 1000. MS Excel: How to convert Number into Words. Below, you will find a wide range of our printable worksheets in chapter Numbers to 1000 of section Numbers and Number Patterns. We do not use the word "thousand", at least not for reading years within the past 1000 years. As a result, for many applications: 1 kilobit (kb) or kilobyte (kB) = 1024 bits or 1024 bytes. New centuries are read as whole numbers of hundreds. This means that 1/4 or 1 in 4 numbers from 1-100 are prime. % Title: 100 HF word cards Author: HP_Administrator Created Date: 9/23/2010 9:40:59 AM. 1-1000 number chart Author: Kim Sutton Created Date: 12/3/2004 3:20:48 PM. I recommend reading about the difference between million and millions and when you should (and should NOT) put an S at the end of the word. The sum of Euler's totient function over the first 57 integers is 1000. Numbers up to 1,000. This is an online math test for fourth grade students free of charge. In the Pages box, indicate the page numbers you want to print. (1) Geneva Conventions Serial Number. Read numbers to 1,000,000 in numerals and words (Y5) 6. And there you have it: Those are all the words you need to spell the first 999 numbers on the number line. This song was written and performed by A. 5, double spaced. All worksheets are free for individual and non-commercial use. Have students place these two piles face up on their desks, making sure not to mix the two. Take a free quiz on what you learned!. As of the late 1960s, the SSN has served as the Geneva Conventions serial number for the Military Services. Note: If a table cell contains multiple lines of text, Word numbers each line in the cell. Filipino Ordinal numbers tell the order of things in a set: first, second, third, etc. After checking a number you can press "Enter" on your keyboard to display a new number. Here are some more. Converting from number word form to standard number notation: 4 millionths = 4 x 10-6 = 0. Prime Number.
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"openwebmath_perplexity": 1984.284467639931,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.7634837635542924,
"lm_q2_score": 0.6548947155710234,
"lm_q1q2_score": 0.5000014821759828
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Numbers In Words 1 To 1000
The above would appear the logical check, but the check treats the date as a number and identifies that number as 1, which is the first part of the number before the slash '/'. Multiplying Decimals by Whole Numbers This is a complete lesson with instruction and varied exercises about how to multiply a whole number by a decimal (fifth grade). Random Word List Print this page, cut out the words, put them in a jar, and use it to draw out random words when you need a stimulus. Numbers in words are written usually with the help of the alphabet. between beyond 1000. mathworksheets4kids. To write numbers in words, start by learning to write the numbers one through nine. For example we find 6 days of work, 8 people in the ark, 10 commandments, 12 tribes of Israel, 12 disciples, 30 pieces of silver, 40 days in the wilderness, 70 prophetic weeks in Daniel, 153 fish in the net, 144,000 on Mount Zion, and 666 - the number of the beast. Based on the Singapore math curr"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Numbers In Words 1 To 1000
The above would appear the logical check, but the check treats the date as a number and identifies that number as 1, which is the first part of the number before the slash '/'. Multiplying Decimals by Whole Numbers This is a complete lesson with instruction and varied exercises about how to multiply a whole number by a decimal (fifth grade). Random Word List Print this page, cut out the words, put them in a jar, and use it to draw out random words when you need a stimulus. Numbers in words are written usually with the help of the alphabet. between beyond 1000. mathworksheets4kids. To write numbers in words, start by learning to write the numbers one through nine. For example we find 6 days of work, 8 people in the ark, 10 commandments, 12 tribes of Israel, 12 disciples, 30 pieces of silver, 40 days in the wilderness, 70 prophetic weeks in Daniel, 153 fish in the net, 144,000 on Mount Zion, and 666 - the number of the beast. Based on the Singapore math curr"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://mathoverflow.net/questions/7957/books-well-motivated-with-explicit-examples
|
# books well-motivated with explicit examples
It is ultimately a matter of personal taste, but I prefer to see a long explicit example, before jumping into the usual definition-theorem path (hopefully I am not the only one here). My problem is that a lot of math books lack the motivating examples or only provide very contrived ones stuck in between pages of definitions and theorems. Reading such books becomes a huge chore for me, even in areas in which I am interested. Besides I am certain no mathematical field was invented by someone coming up with a definition out of thin air and proving theorems with it (that is to say I know the good motivating examples are out there).
Can anyone recommend some graduate level books where the presentation is well-motivated with explicit examples. Any area will do, but the more abstract the field is, the better. I am sure there are tons of combinatorics books that match my description, but I am curious about the "heavier" fields. I don't want this to turn into discussion about the merits of this approach to math (i know Grothendick would disapprove), just want to learn the names of some more books to take a look at them.
Please post one book per answer so other people can vote on it alone. I will start:
Fourier Analysis on Finite Groups and Applications by Terras
PS. this is a similar thread, but the main question is different. How to sufficiently motivate organization of proofs in math books
-
Great question. I look forward to seeing the responses. – John D. Cook Dec 6 '09 at 13:19
Fulton and Harris's "Representation Theory: A First Course". There are three full chapters on representation of $\mathfrak{sl}_2 \mathbb{C}$ and $\mathfrak{sl}_3 \mathbb{C}$ before delving into the general theory.
-
Seconded. In fact, books by Harris tend to be good for this (and Fulton, though not quite as much in my experience) – Charles Siegel Dec 6 '09 at 4:59
They themselves make the case for an example-driven book, saying in effect they don't remember how the abstract proofs go until they run through the cases $sl_2$ and $sl_3$ first. – Todd Trimble Jun 25 '14 at 11:39
Visual Complex Analysis, by Tristan Needham.
Really nice to get a thorough geometrical understanding of (one) complex variable.
-
Thanks for reminding me this book existed. i've been meaning to take a look at it. – Michael Lugo Dec 9 '09 at 2:02
For algebraic geometry, you'll be wanting Joe Harris's "Algebraic Geometry: a First Course"
-
Cox' "Primes of the Form x^2+n*y^2", Cohn's "Introduction of the construction of class fields", Koblitz' "Introduction to elliptic curves and modular forms", Waterhouse's "Affine group schemes". I recomend to look for good surveys in Asterisque, Bull. AMS etc., e.g. I found Katz' "Slope filtrations of F-crystals" in Asterisque 63 or Berger's "Encounter with a Geometer I/II" on Gromov's work, Petersen's "Aspects of global Riemannian geometry" good to read.
-
I think Koblitz' is actually called "Introduction to elliptic curves and modular forms". Maybe you wanted to refer to "Invitation to the mathematics of Fermat-Wiles" by Yves Hellegouarch? – Jose Brox Dec 6 '09 at 17:03
Thanks, corrected now. I didn't read Hellegouach's book, but people described it as excellent. – Thomas Riepe Dec 7 '09 at 9:48
+1 on account of Cox's magnificent book! – stankewicz Mar 14 '10 at 12:57
Koblitz's book is very good, but its biggest problem is that it isn't a very good introduction to modular forms - in relation to what is actually being researched (today). – Dror Speiser Mar 14 '10 at 17:28
@Dror: Care to elaborate? – Justin Hilburn Feb 1 '11 at 2:27
"Differential Topology", Guillemin-Pollack, 1974.
-
The book "Measure theory and probability" by Guillemin and Adams is also very good. – Gonçalo Marques Dec 6 '09 at 18:08
Guillemin is able to make absolutely any topic in mathematicsl both accessible and interesting. – Deane Yang Dec 7 '09 at 0:59
Now we're talking.Even with all the great introductions to differential manifolds out there right now,this is still one of the best. – Andrew L Mar 14 '10 at 8:14
The Topology textbook by Jänich (german, I guess there is an english version by now as well) is quite entertaining and has a lot of very nice motivation. Essentially, the book deals most of the time with motivation only, several theorems are only stated but not prove. However, being so well-motivated this does not even matter so much. I regularly suggest this book to students who want to get some overview before they go into the details (for which you may need some other textbooks as well).
-
+1 for one of my favorite textbooks-but this is really an undergraduate textbook. – Andrew L Jul 14 '12 at 5:01
@Andrew Yepp, of course! it does not go very far and you still need some other topology books, if you really want to get some deeper insight. But for a start, I really like it :) – Stefan Waldmann Jul 16 '12 at 12:21
Three-dimensional geometry and topology: Volume 1 by William Thurston
-
Characteristic classes by Milnor-Stasheff, 1974. This book from Princeton marks (i think) the synthesis of several years of maturation for the real beginnings of modern topology, the next years that came...
In their 20 chapters, preface, 3 appendices, bibliograph and index, anyone gonna see a jewel master piece of math
-
Although I think Whitney's paper "On the topology of differentiable manifolds," Lecture notes in Topology, University of Michigan Press, 1940 is a far more direct motivation -- elegant and to the point. It doesn't dwell on formalities as much as Milnor and Stasheff, but IMO this is a good thing. – Ryan Budney Dec 10 '09 at 21:31
utterly any pro mathematician is going to face modern formal maths :) as high (or worst) as many book on this subject: topology – janmarqz Dec 11 '09 at 4:55
Anyone who doesn't read Milnor and Stasheff will be the very much poorer for it. In fact,anyone who's thinking about writing an advanced mathematics textbook should read it for inspiration. – Andrew L Mar 14 '10 at 8:11
While I certainly like Milnor-Stasheff a lot, I cannot say that it has a wealth of examples. If I remember correctly, it is not even proven that $S^4$ has no almost complex structure! – Lennart Meier Feb 21 at 20:26
Robin Hartshorne just came out with a new book titled "Deformation Theory" based on these lecture notes. It is full of examples and exercises (the latter are not in the online notes).
Chapter 1 of the book is also available (with exercises and an improved exposition) on Springer's website.
-
J. Silverman's "The Arithmetic of Elliptic Curves" is excellent, and has lots of explicit examples throughout the book.
-
Trees by J-P Serre. The first half is pretty much all theory, but in the second he looks at the explicit example of $SL_2$.
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"Riemannian Geometry", Gallot-Hulin-Lafontaine, 1987, plenty of examples and exercises and the motivation: the own one helps...
-
I've always felt that this book, due to the concrete examples, is one of the best books on differential geometry. – Deane Yang Dec 7 '09 at 0:58
Milne's lecture notes contain many good, standard examples discussed in depth. For example, in Algebraic Number Theory, in the section about Frobenius elements, Milne proves quadratic reciprocity (which IMO is the "correct" proof of quadratic reciprocity).
-
I learned point-set topology from the lecture notes by Fernando Chamizo available here: Topología (La Topología de segundo no es tan difícil) (yes, they're in Spanish). They also happen to be the most hilarious mathematics lecture notes I have ever come across.
-
I didn't realize that Sesame Street taught topology. – Michael Lugo Dec 6 '09 at 4:57
Love the subtitle! – Kevin H. Lin Dec 6 '09 at 12:41
You're right. Nice notes and written with great sense of humour. – Gonçalo Marques Dec 6 '09 at 17:22
estan buenisimas las notas! la primera linea que lei: "el ADN (Asociacion Nacional de Dislexicos)?" esta genial!! – Csar Lozano Huerta Dec 8 '09 at 5:01
Peter Petersen's book "Riemannian Geometry" has a whole chapter on examples, most of which are nontrivial ones.
-
Terras, Harmonic analysis on symmetric spaces I, II.
It has some very impressive sections with examples and applications from e.g., solar physics.
-
I agree, but does anyone know why it's out of print? – Gordon Craig Jan 5 '10 at 2:56
Kock/Vainsencher's "An invitation to Quantum Cohomology". The friendliest, best motivated and most fun-to-read book I have ever had in my hands!!
Introduces Moduli of Curves, Gromov-Witten invariants and in the end just the rough idea of Quantum Cohomology.
-
Complex Analysis: Theodore Gamelin's Complex Analysis.Probably the single most user friendly text on the subject there is. Wonderfully written,TONS of examples and covers an enormous breadth of topics.There are lots of good ones on this topic,but for self study,there's probably none better then this one. My one complaint is that Gamelin is sometimes TOO gentle where a proof instead of a picture would be more appropriate. But then the book is designed to be read by a vast audience from freshman to PHD level,so he can be forgiven.
-
Complex functions: an algebraic and geometric viewpoint by Gareth A. Jones, David Singerman
-
+1 for an outstanding geometrically flavored textbook that compliments more "analytic" textbooks on the subject like Conway or Greene/Krantz. – Andrew L Jul 14 '12 at 5:02
A first course in Algebraic topology, again Fulton
-
Boy,is this book overrated,I bought it and thought I was robbed.You want a topology book that follows a historical development,read Stillwell's classic supplemented with McCleary's beautiful little book.Trust me,I just saved you about 60 bucks........ – Andrew L Mar 14 '10 at 8:13
I agree with Andrew L here. I too was disappointed at how little stuff was covered in this book. – Anonymous Mar 14 '10 at 16:03
"Explorations in Monte Carlo Methods" by Shonkwiler and Mendivil. Everything is well-motivated by examples. However, it is an undergraduate book.
-
Foliations 1 by Alberto Candel and Lawrence Conlon
-
Complex Analysis by Raghavan Narasimhan
-
Algebraic curves and Riemann surfaces by Rick Miranda
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IMHO, algebraic geometry books by Joe Harris are very naturally written: every definition or theorem comes up when you are ready or even expect it, and if you do not understand something, it is probably written on the next page.
-
Model Theory: An Introduction by David Marker. A chief strength of this introduction (to what is after all a fairly abstract field) is the working through of explicit examples from all over mathematics, e.g., definability and interpretability of structures, applications of back-and-forth arguments, and so on.
Another good "model theory" book is van den Dries, Tame topology and o-minimal structures. Here it's not so much that many examples are given as it is that a few well-chosen examples are constantly at hand to illustrate the development. I put "model theory" in quotes because in fact the author keeps the model-theoretic jargon to a minimum throughout (even though there is no doubt that model theory informs the development); this makes the book very accessible to a wide audience.
These examples suggest to me that some of my category-theoretic brothers and sisters could take a page from some of these model theory books. It has to be understood that many examples in category theory are not of single objects but rather of categories and mini-theories (so one may have to to readjust one's expectations here), but even so, I find some articles in category theory mildly exasperating when they lack examples even of this type.
-
Lectures on Polytopes (Graduate Texts in Mathematics) by Günter M. Ziegler .
-
O. Ya. Viro, O. A. Ivanov, N. Yu. Netsvetaev, V. M. Kharlamov, Elementary Topology Problem Textbook has lots of examples.
-
I can give a couple of dozen examples-but for now,I'll just list my favorite for topology/geometry: The trilogy by John M.Lee is probably the best written,laid out and flat out wonderful introduction to the study of differential and Riemannian manifolds there is for anyone looking to learn it on thier own. I hate to say it,but it's better then Spivak's opus.
-
| 2015-04-01T16:56:18 |
{
"domain": "mathoverflow.net",
"url": "http://mathoverflow.net/questions/7957/books-well-motivated-with-explicit-examples",
"openwebmath_score": 0.5476623773574829,
"openwebmath_perplexity": 1512.1012601235507,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542924,
"lm_q2_score": 0.6548947155710234,
"lm_q1q2_score": 0.5000014821759828
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# books well-motivated with explicit examples
It is ultimately a matter of personal taste, but I prefer to see a long explicit example, before jumping into the usual definition-theorem path (hopefully I am not the only one here). My problem is that a lot of math books lack the motivating examples or only provide very contrived ones stuck in between pages of definitions and theorems. Reading such books becomes a huge chore for me, even in areas in which I am interested. Besides I am certain no mathematical field was invented by someone coming up with a definition out of thin air and proving theorems with it (that is to say I know the good motivating examples are out there).
Can anyone recommend some graduate level books where the presentation is well-motivated with explicit examples. Any area will do, but the more abstract the field is, the better. I am sure there are tons of combinatorics books that match my description, but I am curious about the "heavier" fields. I don't want this "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# books well-motivated with explicit examples
It is ultimately a matter of personal taste, but I prefer to see a long explicit example, before jumping into the usual definition-theorem path (hopefully I am not the only one here). My problem is that a lot of math books lack the motivating examples or only provide very contrived ones stuck in between pages of definitions and theorems. Reading such books becomes a huge chore for me, even in areas in which I am interested. Besides I am certain no mathematical field was invented by someone coming up with a definition out of thin air and proving theorems with it (that is to say I know the good motivating examples are out there).
Can anyone recommend some graduate level books where the presentation is well-motivated with explicit examples. Any area will do, but the more abstract the field is, the better. I am sure there are tons of combinatorics books that match my description, but I am curious about the "heavier" fields. I don't want this "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://cs.roanoke.edu/Spring2016/CPSC170A/lectures.php?lec=24
|
## Lecture 24 - Backtracking
As usual, create a directory to hold today's activities:
$mkdir ~/cs170/labs/lab24$ cd ~/cs170/labs/lab24
Pop Quiz!
The following problem is to be solved individually, on your computer. You may look at any old files you desire for this activity, but you may not consult any other webpages. You have 15 minutes to complete this quiz.
#### Missing Letters
Write a function called missing_letters(a_string), which takes a string as a parameter. Your function should return (in alphabetical order), the letters that are missing from the passed string. You can assume all of the letters are lower case in the string. There are also spaces in the string.
For this program, you should start by creating a list that contains the letters a through z. You must follow this algorithm. Alternate solutions will not be graded. Use a for loop to iterate over the letters in the string parameter. Every time you see a letter in the string, remove it from the list. Then, at the end, write a for loop to merge the letters from the list into a string.
#### Examples
>>> print("Missing Letters:",
missing_letters("the quick brown fox jumps over the lazy dog"))
Missing Letters:
>>> print("Missing Letters:",
missing_letters("the quick brown fox jumped over the lazy dog"))
Missing Letters: s
#### Submission
Submit to inquire, under the link for Pop Quiz #2.
### Backtracking and Sudoku
Today is the day that we will begin looking at the relationship between stacks and recursion. The big relationship between them is through the class of algorithms known as backtracking. Backtracking can be thought of as a directed brute-force approach, but through the backtracking mechanism you ultimately don't end up performing a full brute-force approach. Let's take a look at how we could use recursion to perform the maze solution, and how it operates.
Lab Activity 1
Eight Queens
Many people consider the Queen in a game of chess to be the most powerful piece to own. This may be largely because of the mobility the queen piece affords. If you are unfamiliar with chess, the Queen is the only piece that can move in the four cardinal directions, as well as the four diagonals. And the Queen can move as far as she wants in any of these directions.
This mobility of the queen sparked one of the more interesting logic puzzles related to chess: On an $$8 \times 8$$ sized chess board, is there a way to place 8 queens on the board such that none of the queens can "take" one another?
#### Details
Your job is to write a program that recursively tries to place 8 queens on an $$8 \times 8$$ chess board, such that none of the queens can take one another. To accomplish this, you will write a backtracking algorithm similar to the maze traversal program covered in class.
Key things to note are that once you have placed a queen on a given column of the board, you cannot place another queen in that column. As such, you only need to try placing queens somewhere in each of the columns of the board.
For this program, you will be representing the board as an $$8 \times 8$$ 2-d list. A $$0$$ will represent an empty location on the board, while the string $$Q$$ will represent a location which holds a Queen.
START ON PAPER! Try mechanically placing queens on the chess board on paper. Can you trace through and find a solution manually? If you can find the solution manually, you should be able to write an algorithm that will mimic what you did on paper.
#### Hint
• First, it will be prudent to write a function called check_board(chess_board, row, col), which takes the current state of the chess_board and returns $$True$$ only if none of the queens on the board can take the position specified by row and column. Otherwise, this function should return False.
The most difficult part of this function is the diagonal check. Keep in mind that you do not need to check AHEAD of the current column. Since you are filling columns from left to right, you only need to check the diagonals BEHIND the column you are trying to be set.
You need a loop to compute the diagonals. You can use a for loop if you can figure out the size of the diagonal. If not, just use a while loop. In the diagonals, you need to change the row and column indices at the same rate. To get the "upper" diagonal, you will subtract the same amount from row and column. For the "lower" diagonal, you will add to row, and subtract from column.
• Write a recursive function called place_queen(chess_board, column), which should try to place a queen in the specified column of the chess board. Do you think this function needs to return anything?
• Your base case for the recursion should simply be that you have successfully placed all of the queens on the board. And in this case you want to print the state of the board.
### Challenge
The full, formal definition of the logic puzzle described above asks if it is possible to place $$N$$ queens on an $$N \times N$$ chessboard. If you write your program well enough, this should be a simple change to make. Try out a few different chess board sizes. Can you determine what sizes of boards have solutions? Write up your findings in comments of your file.
#### Submission
When you have finished, create a tar file of your lab24 directory. To create a tar file, execute the following commands:
cd ~/cs170/labs
tar czvf lab24.tgz lab24/
To submit your activity, go to inquire.roanoke.edu. You should see an available assignment called Lab Assignment 24. Make sure you include a header listing the authors of the file.
| 2022-12-08T17:52:19 |
{
"domain": "roanoke.edu",
"url": "http://cs.roanoke.edu/Spring2016/CPSC170A/lectures.php?lec=24",
"openwebmath_score": 0.3634973168373108,
"openwebmath_perplexity": 544.261205983199,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542925,
"lm_q2_score": 0.6548947155710233,
"lm_q1q2_score": 0.5000014821759827
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"## Lecture 24 - Backtracking
As usual, create a directory to hold today's activities:
$mkdir ~/cs170/labs/lab24$ cd ~/cs170/labs/lab24
Pop Quiz!
The following problem is to be solved individually, on your computer. You may look at any old files you desire for this activity, but you may not consult any other webpages. You have 15 minutes to complete this quiz.
#### Missing Letters
Write a function called missing_letters(a_string), which takes a string as a parameter. Your function should return (in alphabetical order), the letters that are missing from the passed string. You can assume all of the letters are lower case in the string. There are also spaces in the string.
For this program, you should start by creating a list that contains the letters a through z. You must follow this algorithm. Alternate solutions will not be graded. Use a for loop to iterate over the letters in the string parameter. Every time you see a letter in the string, remove it from the list. Then, at the "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"## Lecture 24 - Backtracking
As usual, create a directory to hold today's activities:
$mkdir ~/cs170/labs/lab24$ cd ~/cs170/labs/lab24
Pop Quiz!
The following problem is to be solved individually, on your computer. You may look at any old files you desire for this activity, but you may not consult any other webpages. You have 15 minutes to complete this quiz.
#### Missing Letters
Write a function called missing_letters(a_string), which takes a string as a parameter. Your function should return (in alphabetical order), the letters that are missing from the passed string. You can assume all of the letters are lower case in the string. There are also spaces in the string.
For this program, you should start by creating a list that contains the letters a through z. You must follow this algorithm. Alternate solutions will not be graded. Use a for loop to iterate over the letters in the string parameter. Every time you see a letter in the string, remove it from the list. Then, at the "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://tex.stackexchange.com/questions/34754/best-way-to-create-colored-text-boxes
|
# Best way to create colored text boxes
I am retyping some old exams into LaTeX, and I encountered the page below
Now with some clever commands, and whatnot I was able to create something almost identical. Though the spacing is a tad off, and my equation is a tad small. I also had to use some hacks and ugly code to produce the result
Does anyone have a better cleaner way to do this ?
Here is almost the exact code I am using for typesetting these exams. Only difference is that all the "junk" in the header is placed i sty. files. So y header contains only 3-5 input files. Here I included everything that is needed to run the code. Some improvements to the code below would be great.
\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{mathtools}
\usepackage{xstring}
\usepackage{xparse}
\newcounter{tittel}
\setcounter{tittel}{0}
\newcounter{problem}
\setcounter{problem}{0}
\newcounter{alternative}
\setcounter{alternative}{0}
\newcounter{navn}[problem]
\renewcommand{\thenavn}{\alph{navn}}
\newcommand{\navn}{\stepcounter{navn}\paragraph*{\thenavn)}}
\setcounter{navn}{0}
\newcommand{\NR}[1]
{ \vspace{5mm} \begin{minipage}[t]{0.051 \textwidth}
\navn \hspace{0pt}
\end{minipage}
\begin{minipage}[t]{0.949\textwidth}
#1
\end{minipage}
\vspace{-0.3cm}
}
\newif\iffirstalt
\NewDocumentCommand{\Oppgave}{m o}{%
\IfNoValueTF{#2}{\setcounter{alternative}{0}\stepcounter{problem} \firstaltfalse}%
{\stepcounter{alternative}\iffirstalt\else\stepcounter{problem} \firstalttrue\fi}
\section*{Oppgave \arabic{problem}%
{\normalfont\IfNoValueTF{#2}{}{~Alternative \Roman{alternative}\ }
\normalsize (#1 poeng)}%
\vspace{3mm} }
\begin{document}
\Oppgave{5}
En gruppe på $8$ elever besår av like mange gutter som jenter. Vi trekker tilfeldig ut 8 elever.
\NR{ Hva er sannsynligheten for å trekke ut $2$ gutter og $1$ jente? }
\NR{ Hva er sannsynligheten for å trekke ut minst $1$ jente? }
\begin{center}
\noindent\fcolorbox{black}{LightSteelBlue}{%
\parbox[t][3cm][c]{11cm}{ \hspace*{0.25cm} Hypergeometrisk sannsynlighetsfordeling: $\displaystyle P(X=x)=\dfrac{\binom{m}{k}\binom{n-m}{r-k}}{\binom{n}{r}}$ \\
\hspace*{0.25cm} $m$ elementer i $D$. $n-m$ elementer i $\bar{D}$ \\
\hspace*{0.25cm} $r$ elementer trekkes tilfeldig. \\
\hspace*{0.25cm} $X$ er antall elementer som trekkes fra $D$ }%
}%
\end{center}
\end{document}
Below is a minimal example, barely enough to produce the page above.
\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{mathtools}
\begin{document}
\section*{Oppgave 2 \normalsize \normalfont (5 poeng)}
En gruppe på $8$ elever besår av like mange gutter som jenter. Vi trekker tilfeldig ut 8 elever.
\paragraph*{a)} Hva er sannsynligheten for å trekke ut $2$ gutter og $1$ jente?
\paragraph*{b)} Hva er sannsynligheten for å trekke ut minst $1$ jente?
\begin{center}
\noindent\fcolorbox{black}{LightSteelBlue}{%
\parbox[t][3cm][c]{11cm}{ \hspace*{0.25cm} Hypergeometrisk sannsynlighetsfordeling: $\displaystyle P(X=x)=\dfrac{\binom{m}{k}\binom{n-m}{r-k}}{\binom{n}{r}}$ \\
\hspace*{0.25cm} $m$ elementer i $D$. $n-m$ elementer i $\bar{D}$ \\
\hspace*{0.25cm} $r$ elementer trekkes tilfeldig. \\
\hspace*{0.25cm} $X$ er antall elementer som trekkes fra $D$ }%
}%
\end{center}
\end{document}
Here is how my output looks
Question(s)
• Is there an easier way, that also looks better for creating the blue box?
• Are there any smal improvements that could be done to my "long" code?
-
Yesterday I uploaded mdframed v1.0. There is an example which produces your output. – Marco Daniel Nov 14 '11 at 6:08
You mention that your formula was a bit small: to fix that use \dbinom instead of \binom. This needs amsmath which is already included by mathtools'. – Peter Grill Nov 14 '11 at 18:18
Here a way to define such a box using adjustbox. See the manual for more options.
\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{mathtools}
\usepackage{xstring}
\usepackage{xparse}
\usepackage{varwidth}
\newcounter{tittel}
\setcounter{tittel}{0}
\newcounter{problem}
\setcounter{problem}{0}
\newcounter{alternative}
\setcounter{alternative}{0}
\newcounter{navn}[problem]
\renewcommand{\thenavn}{\alph{navn}}
\newcommand{\navn}{\stepcounter{navn}\paragraph*{\thenavn)}}
\setcounter{navn}{0}
\newcommand{\NR}[1]
{ \vspace{5mm} \begin{minipage}[t]{0.051 \textwidth}
\navn \hspace{0pt}
\end{minipage}
\begin{minipage}[t]{0.949\textwidth}
#1
\end{minipage}
\vspace{-0.3cm}
}
\newif\iffirstalt
\NewDocumentCommand{\Oppgave}{m o}{%
\IfNoValueTF{#2}{\setcounter{alternative}{0}\stepcounter{problem} \firstaltfalse}%
{\stepcounter{alternative}\iffirstalt\else\stepcounter{problem} \firstalttrue\fi}
\section*{Oppgave \arabic{problem}%
{\normalfont\IfNoValueTF{#2}{}{~Alternative \Roman{alternative}\ }
\normalsize (#1 poeng)}%
\vspace{3mm} }
\newenvironment{bluebox}{%
\noindent
}{%
\egroup
}
\begin{document}
\Oppgave{5}
En gruppe på $8$ elever besår av like mange gutter som jenter. Vi trekker tilfeldig ut 8 elever.
\NR{ Hva er sannsynligheten for å trekke ut $2$ gutter og $1$ jente? }
\NR{ Hva er sannsynligheten for å trekke ut minst $1$ jente? }
\begin{bluebox}
Hypergeometrisk sannsynlighetsfordeling: $\displaystyle P(X=x)=\dfrac{\binom{m}{k}\binom{n-m}{r-k}}{\binom{n}{r}}$ \\
$m$ elementer i $D$. $n-m$ elementer i $\bar{D}$ \\
$r$ elementer trekkes tilfeldig. \\
$X$ er antall elementer som trekkes fra $D$
\end{bluebox}
\end{document}
-
It seems as both of these solutions deppends on that I know how wide and tall the box is supposed to be. Is there any way to adjust the height and width of the box automaticaly? Thanks a lot for your answer =) – N3buchadnezzar Nov 14 '11 at 9:12
Yes, use the varwidth environment from the package with the same name. I actually just now release a new version of adjustbox which has a varwidth key, but you can use it without it as well. – Martin Scharrer Nov 14 '11 at 9:39
@N3buchadnezzar: See my updated answer. The varwidth environment takes a maximal width argument, but uses the normal width of the content. – Martin Scharrer Nov 14 '11 at 9:46
Really cool. Thanks a bunch! Will look into that package. Does this also change the height of the box? I am not too conserned about page breaks. As these boxes will always range from half a page to a sentence. – N3buchadnezzar Nov 14 '11 at 9:51
varwidth accepts the same arguments like minipage or \parbox, so you can also give an optional height argument. However, if you simply want to add some height, i.e. vertical padding, I would use the margin key of adjustbox, which can also be used multiple times. – Martin Scharrer Nov 14 '11 at 9:56
Here a solution with mdframed. Other possibilities are the packages adjustbox or you simple use tikz (no page breaks available).
The new version is uploaded to CTAN. If you want to test the current example the package can be downloaded here (include also the new documentations)
According to your numbering of paragraphs I would create a new command which does it for you.
\documentclass{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage{amsmath}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage[framemethod=default]{mdframed}
\mdfdefinestyle{NR}{skipabove=\topskip,skipbelow=\topskip,%
,align=center,%
innerleftmargin=.25cm,linecolor=black,%
linewidth=2pt,backgroundcolor=LightSteelBlue}
\newmdenv[style=NR]{NR}
\newcounter{myparagraph}
\setcounter{myparagraph}{0}
\usepackage{showframe}
\begin{document}
\myparagraph{Hva er sannsynligheten for å trekke ut $2$ gutter og $1$ jente?}
\myparagraph{Hva er sannsynligheten for å trekke ut minst $1$ jente?}
\begin{NR}[userdefinedwidth=11cm]
Hypergeometrisk sannsynlighetsfordeling: $\displaystyle P(X=x)=\dfrac{\binom{m}{k}\binom{n-m}{r-k}}{\binom{n}{r}}$ \\
$m$ elementer i $D$. $n-m$ elementer i $\bar{D}$ \\
$r$ elementer trekkes tilfeldig. \\
$X$ er antall elementer som trekkes fra $D$
\end{NR}
\end{document}
-
It seems as both of these solutions deppends on that I know how wide and tall the box is supposed to be. Is there any way to adjust the height and width of the box automaticaly? Thanks a lot for your answer =) – N3buchadnezzar Nov 14 '11 at 9:13
\newenvironment{bluebox}
{\begin{lrbox}{0}\begin{tabular}{@{}l@{}}}
{\end{tabular}\end{lrbox}%
`
| 2016-06-30T06:56:16 |
{
"domain": "stackexchange.com",
"url": "http://tex.stackexchange.com/questions/34754/best-way-to-create-colored-text-boxes",
"openwebmath_score": 0.9814326763153076,
"openwebmath_perplexity": 8547.802253373648,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542924,
"lm_q2_score": 0.6548947155710233,
"lm_q1q2_score": 0.5000014821759827
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Best way to create colored text boxes
I am retyping some old exams into LaTeX, and I encountered the page below
Now with some clever commands, and whatnot I was able to create something almost identical. Though the spacing is a tad off, and my equation is a tad small. I also had to use some hacks and ugly code to produce the result
Does anyone have a better cleaner way to do this ?
Here is almost the exact code I am using for typesetting these exams. Only difference is that all the "junk" in the header is placed i sty. files. So y header contains only 3-5 input files. Here I included everything that is needed to run the code. Some improvements to the code below would be great.
\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{mathtools}
\usepackage{xstring}
\usepackage{xparse}
\newcounter{tittel}
\setcounter{tittel}{0}
\newcounter{proble"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Best way to create colored text boxes
I am retyping some old exams into LaTeX, and I encountered the page below
Now with some clever commands, and whatnot I was able to create something almost identical. Though the spacing is a tad off, and my equation is a tad small. I also had to use some hacks and ugly code to produce the result
Does anyone have a better cleaner way to do this ?
Here is almost the exact code I am using for typesetting these exams. Only difference is that all the "junk" in the header is placed i sty. files. So y header contains only 3-5 input files. Here I included everything that is needed to run the code. Some improvements to the code below would be great.
\documentclass[10pt,a4paper]{article}
\usepackage[hmargin=3cm,vmargin=2cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[norsk]{babel}
\usepackage[dvipsnames*,svgnames]{xcolor}
\usepackage{mathtools}
\usepackage{xstring}
\usepackage{xparse}
\newcounter{tittel}
\setcounter{tittel}{0}
\newcounter{proble"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://codereview.stackexchange.com/questions/33291/improving-efficiency-for-finding-longest-contiguous-non-decreasing-substring
|
# Improving efficiency for finding longest contiguous non-decreasing substring
I was working on a problem set and I came across this problem:
Assume s is a string of lower case characters.
Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, if s = 'azcbobobegghakl', then your program should print:
Longest substring in alphabetical order is: beggh
In the case of ties, print the first substring. For example, if s = 'abcbcd', then your program should print
Longest substring in alphabetical order is: abc
I actually was able to get a solution, but it was the most inefficient ever! And here's what I came up with:
def test():
index = 1
prev_index = 0
count = 0
global largest
largest = ''
test = s[prev_index]
while count < len(s):
if ord(s[index]) > ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
elif ord(s[index]) == ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
else:
if len(largest) < len(test):
largest = test[:]
test = s[index]
prev_index += 1
index += 1
count += 1
return largest
try:
test()
except IndexError:
pass
finally:
print largest
Can anyone give me an example of better code that produces the same output?
Your algorithm is basically fine, but it is expressed in the code clumsily.
The biggest problem is the interface of the function: it should accept a string parameter and return a string. Instead, your function takes s from its environment and uses the global variable largest to store the answer. Although there is a return largest statement, it is very misleading. What actually happens is that s[index] raises an IndexError, so that the return largest is never reached, and the answer is passed back using the global variable instead.
The root cause for the IndexError is that there are too many variables, causing confusion. With each iteration through the loop, you increment index, prev_index, and count. That means that those three variables could be reduced to one, which could just be called i. (If you think about it, you'll find that count is always one less than index. Since the loop condition is count < len(s), s[index] will go one position beyond the end of the string.)
The next observation to make is that your if and elif blocks are almost identical. You can combine them by using >= for the test.
Python strings are immutable, so largest = test[:] could just be largest = test.
Putting everything together…
def longest_nondecreasing_substring(s):
if s is None or len(s) <= 1:
return s
longest = test = s[0]
for i in range(1, len(s)):
if ord(s[i]) >= ord(s[i - 1]):
test += s[i]
else:
if len(longest) < len(test):
longest = test
test = s[i]
if len(longest) < len(test):
longest = test
return longest
• What, no docstring? Oct 28 '13 at 10:26
This answer doesn't have docstrings (Python isn't my main language), but the basic idea is to just start at every character and see how far you can go:
def longest_nondecreasing(s):
start = -1
maxlen = -1
for i in range(len(s)):
for j in range(i+1, len(s)):
if s[j] < s[i]:
break
else: # we made it to the end!
j = len(s)
#so now our nondecreasing string goes from i to j
if j - i > maxlen:
maxlen = j - i
start = i
return s[start:start + maxlen]
Once we have a working solution, we can work on making some optimizations. For instance, if we have one contiguous non-decreasing sequence from say... 4 to 9, we definitely know that the longest non-decreasing sequence starting at 5 will also end at 9. Hence after the j loop we can just set i to j.
It's the famous Longest increasing subsequence problem. Convert the chars to ints using the ord function
def longest_increasing_subsequence(X):
"""
Find and return longest increasing subsequence of S.
If multiple increasing subsequences exist, the one that ends
with the smallest value is preferred, and if multiple
occurrences of that value can end the sequence, then the
earliest occurrence is preferred.
"""
n = len(X)
X = [None] + X # Pad sequence so that it starts at X[1]
M = [None]*(n+1) # Allocate arrays for M and P
P = [None]*(n+1)
L = 0
for i in range(1,n+1):
if L == 0 or X[M[1]] >= X[i]:
# there is no j s.t. X[M[j]] < X[i]]
j = 0
else:
# binary search for the largest j s.t. X[M[j]] < X[i]]
lo = 1 # largest value known to be <= j
hi = L+1 # smallest value known to be > j
while lo < hi - 1:
mid = (lo + hi)//2
if X[M[mid]] < X[i]:
lo = mid
else:
hi = mid
j = lo
P[i] = M[j]
if j == L or X[i] < X[M[j+1]]:
M[j+1] = i
L = max(L,j+1)
# Backtrack to find the optimal sequence in reverse order
output = []
pos = M[L]
while L > 0:
output.append(X[pos])
pos = P[pos]
L -= 1
output.reverse()
return output
def main():
TEST_STRING = 'azcbobobegghakl'
print(''.join(map(chr, longest_increasing_subsequence(map(ord, TEST_STRING)))))
if __name__ == '__main__':
main()
• In the OP's problem it's clear that the sequence must be contiguous (consider the first example, where the answer is beggh, not abegghkl). So your answer is solving a different problem. Oct 26 '13 at 18:54
• The example was invisible and there aren't any word about contiguous sequence only. Oct 26 '13 at 19:16
• The OP may have been poorly formatted but the example was not invisible if you read it carefully. Oct 26 '13 at 19:20
| 2021-10-28T03:56:53 |
{
"domain": "stackexchange.com",
"url": "https://codereview.stackexchange.com/questions/33291/improving-efficiency-for-finding-longest-contiguous-non-decreasing-substring",
"openwebmath_score": 0.4395616352558136,
"openwebmath_perplexity": 3123.860762163774,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837635542925,
"lm_q2_score": 0.6548947155710233,
"lm_q1q2_score": 0.5000014821759827
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Improving efficiency for finding longest contiguous non-decreasing substring
I was working on a problem set and I came across this problem:
Assume s is a string of lower case characters.
Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, if s = 'azcbobobegghakl', then your program should print:
Longest substring in alphabetical order is: beggh
In the case of ties, print the first substring. For example, if s = 'abcbcd', then your program should print
Longest substring in alphabetical order is: abc
I actually was able to get a solution, but it was the most inefficient ever! And here's what I came up with:
def test():
index = 1
prev_index = 0
count = 0
global largest
largest = ''
test = s[prev_index]
while count < len(s):
if ord(s[index]) > ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
elif ord(s[index]) == ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
else:
if len(largest)"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Improving efficiency for finding longest contiguous non-decreasing substring
I was working on a problem set and I came across this problem:
Assume s is a string of lower case characters.
Write a program that prints the longest substring of s in which the letters occur in alphabetical order. For example, if s = 'azcbobobegghakl', then your program should print:
Longest substring in alphabetical order is: beggh
In the case of ties, print the first substring. For example, if s = 'abcbcd', then your program should print
Longest substring in alphabetical order is: abc
I actually was able to get a solution, but it was the most inefficient ever! And here's what I came up with:
def test():
index = 1
prev_index = 0
count = 0
global largest
largest = ''
test = s[prev_index]
while count < len(s):
if ord(s[index]) > ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
elif ord(s[index]) == ord(s[prev_index]):
test += s[index]
index += 1
prev_index += 1
else:
if len(largest)"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://new-contents.com/Maine/from-standard-error-to-standard-deviation.html
|
Address 57 Court St, Houlton, ME 04730 (207) 694-0423 http://www.aroostookcomputertutor.com
# from standard error to standard deviation Sherman Mills, Maine
A quantitative measure of uncertainty is reported: a margin of error of 2%, or a confidence interval of 18 to 22. The standard deviation of the age for the 16 runners is 10.23. It is rare that the true population standard deviation is known. Why is the spacesuit design so strange in Sunshine?
up vote 17 down vote favorite 6 Is it sensible to convert standard error to standard deviation? R+H2O for marketing campaign modeling Watch: Highlights of the Microsoft Data Science Summit A simple workflow for deep learning gcbd 0.2.6 RcppCNPy 0.2.6 Using R to detect fraud at 1 million However, the mean and standard deviation are descriptive statistics, whereas the standard error of the mean describes bounds on a random sampling process. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
A medical research team tests a new drug to lower cholesterol. When we calculate the standard deviation of a sample, we are using it as an estimate of the variability of the population from which the sample was drawn. Standard Error of Sample Estimates Sadly, the values of population parameters are often unknown, making it impossible to compute the standard deviation of a statistic. If one survey has a standard error of $10,000 and the other has a standard error of$5,000, then the relative standard errors are 20% and 10% respectively.
A natural way to describe the variation of these sample means around the true population mean is the standard deviation of the distribution of the sample means. As the standard error is a type of standard deviation, confusion is understandable. Jobs for R usersFinance Manager @ Seattle, U.S.Data Scientist – AnalyticsTransportation Market Research Analyst @ Arlington, U.S.Data AnalystData Scientist for Madlan @ Tel Aviv, IsraelBioinformatics Specialist @ San Francisco, U.S.Postdoctoral Scholar National Center for Health Statistics typically does not report an estimated mean if its relative standard error exceeds 30%. (NCHS also typically requires at least 30 observations – if not more
What sense of "hack" is involved in five hacks for using coffee filters? The margin of error and the confidence interval are based on a quantitative measure of uncertainty: the standard error. Retrieved 17 July 2014. Terms and Conditions for this website Never miss an update!
R code to accompany Real-World Machine Learning (Chapter 2) GoodReads: Machine Learning (Part 3) One Way Analysis of Variance Exercises Most visited articles of the week How to write the first The standard deviation of all possible sample means of size 16 is the standard error. By contrast the standard deviation will not tend to change as we increase the size of our sample.So, if we want to say how widely scattered some measurements are, we use For a value that is sampled with an unbiased normally distributed error, the above depicts the proportion of samples that would fall between 0, 1, 2, and 3 standard deviations above
The standard error of the mean is the expected value of the standard deviation of means of several samples, this is estimated from a single sample as: [s is standard deviation It can only be calculated if the mean is a non-zero value. Learn R R jobs Submit a new job (it's free) Browse latest jobs (also free) Contact us Welcome! The true standard error of the mean, using σ = 9.27, is σ x ¯ = σ n = 9.27 16 = 2.32 {\displaystyle \sigma _{\bar {x}}\ ={\frac {\sigma }{\sqrt
It will be shown that the standard deviation of all possible sample means of size n=16 is equal to the population standard deviation, σ, divided by the square root of the These formulas are valid when the population size is much larger (at least 20 times larger) than the sample size. This is not the case when there are extreme values in a distribution or when the distribution is skewed, in these situations interquartile range or semi-interquartile are preferred measures of spread. doi:10.4103/2229-3485.100662. ^ Isserlis, L. (1918). "On the value of a mean as calculated from a sample".
doi:10.2307/2340569. T-distributions are slightly different from Gaussian, and vary depending on the size of the sample. If a variable y is a linear (y = a + bx) transformation of x then the variance of y is b² times the variance of x and the standard deviation The age data are in the data set run10 from the R package openintro that accompanies the textbook by Dietz [4] The graph shows the distribution of ages for the runners.
Full list of contributing R-bloggers R-bloggers was founded by Tal Galili, with gratitude to the R community. Whether or not that formula is appropriate depends on what statistic we are talking about. Statistic Standard Deviation Sample mean, x σx = σ / sqrt( n ) Sample proportion, p σp = sqrt [ P(1 - P) / n ] Difference between means, x1 - The divisor for the experimental intervention group is 4.128, from above.
The data set is ageAtMar, also from the R package openintro from the textbook by Dietz et al.[4] For the purpose of this example, the 5,534 women are the entire population Because the age of the runners have a larger standard deviation (9.27 years) than does the age at first marriage (4.72 years), the standard error of the mean is larger for The sample proportion of 52% is an estimate of the true proportion who will vote for candidate A in the actual election. The standard deviation for each group is obtained by dividing the length of the confidence interval by 3.92, and then multiplying by the square root of the sample size: For 90%
Interquartile range is the difference between the 25th and 75th centiles. These assumptions may be approximately met when the population from which samples are taken is normally distributed, or when the sample size is sufficiently large to rely on the Central Limit NLM NIH DHHS USA.gov National Center for Biotechnology Information, U.S. Gurland and Tripathi (1971)[6] provide a correction and equation for this effect.
ISBN 0-8493-2479-3 p. 626 ^ a b Dietz, David; Barr, Christopher; Çetinkaya-Rundel, Mine (2012), OpenIntro Statistics (Second ed.), openintro.org ^ T.P. more hot questions question feed about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation Science Consider the following scenarios.
| 2018-12-10T13:41:12 |
{
"domain": "new-contents.com",
"url": "http://new-contents.com/Maine/from-standard-error-to-standard-deviation.html",
"openwebmath_score": 0.6239083409309387,
"openwebmath_perplexity": 995.8197008372085,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES\n\n",
"lm_q1_score": 0.7634837635542924,
"lm_q2_score": 0.6548947155710233,
"lm_q1q2_score": 0.5000014821759827
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"Address 57 Court St, Houlton, ME 04730 (207) 694-0423 http://www.aroostookcomputertutor.com
# from standard error to standard deviation Sherman Mills, Maine
A quantitative measure of uncertainty is reported: a margin of error of 2%, or a confidence interval of 18 to 22. The standard deviation of the age for the 16 runners is 10.23. It is rare that the true population standard deviation is known. Why is the spacesuit design so strange in Sunshine?
up vote 17 down vote favorite 6 Is it sensible to convert standard error to standard deviation? R+H2O for marketing campaign modeling Watch: Highlights of the Microsoft Data Science Summit A simple workflow for deep learning gcbd 0.2.6 RcppCNPy 0.2.6 Using R to detect fraud at 1 million However, the mean and standard deviation are descriptive statistics, whereas the standard error of the mean describes bounds on a random sampling process. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
A m"
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Here's an extract from a webpage:
"Address 57 Court St, Houlton, ME 04730 (207) 694-0423 http://www.aroostookcomputertutor.com
# from standard error to standard deviation Sherman Mills, Maine
A quantitative measure of uncertainty is reported: a margin of error of 2%, or a confidence interval of 18 to 22. The standard deviation of the age for the 16 runners is 10.23. It is rare that the true population standard deviation is known. Why is the spacesuit design so strange in Sunshine?
up vote 17 down vote favorite 6 Is it sensible to convert standard error to standard deviation? R+H2O for marketing campaign modeling Watch: Highlights of the Microsoft Data Science Summit A simple workflow for deep learning gcbd 0.2.6 RcppCNPy 0.2.6 Using R to detect fraud at 1 million However, the mean and standard deviation are descriptive statistics, whereas the standard error of the mean describes bounds on a random sampling process. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
A m"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://faqoverflow.kranzky.com/mathematica/2449.html
|
# FAQ overflow
#### QUESTION
I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical example
a + b + c
which has FullForm
Plus[a, b, c]
We expect, then, (a+b+c)[[0]] === Plus === Head[a+b+c] to be True, and it is. But then, we would expect (a+b+c)[[1;;3]] would be {a, b, c}, wouldn't we? But it isn't. The following is true:
(a + b + c)[[1;;3]] === (a + b + c)
Somehow, [[1;;3]], which is supposed to pick off elements 1 through 3 of its argument and put them in a List, doesn't get rid of the Head, which is element 0!
The questions are, then (and I will be grateful for hints and answers!)
1. Why doesn't (a + b + c)[[1;;3]] get rid of (a + b + c)[[0]], the Head?
2. What is the right way to get rid of the Head?
3. (a + b + c)[[0;;3]] produces 0. I would expect it to produce {Plus, a, b, c}. Instead, it produces 0. This just deepens the mystery for me! Why?
###### Point #1
Part always wraps element sequences with the original head of the expression.
expr = Hold[1 + 1, 2 + 2, 3 + 3, 4 + 4, 5 + 5];
expr[[{2, 3}]]
Hold[2 + 2, 3 + 3]
For this purpose a single part e.g. 1 is not a sequence but {1} and 1 ;; 1 are:
expr[[1]]
expr[[{1}]]
expr[[1 ;; 1]]
2
Hold[1 + 1]
Hold[1 + 1]
This applies at every level of the extraction:
expr = g[h[1, 2], i[3, 4]];
expr[[ 2 , 1 ]]
expr[[ {2}, 1 ]]
expr[[ 2 ,{1} ]]
expr[[ {2},{1} ]]
3
g[3]
i[3]
g[i[3]]
I used this nontrivially for Elegant manipulation of the variables list.
###### Point #2
Consider instead using Extract which wraps sequences in List:
Extract[expr, {{2}, {3}}]
{4, 6}
The third argument of Extract can be used to specify a function to apply to individual elements before they are evaluated:
Extract[expr, {{2}, {3}}, HoldForm]
{2 + 2, 3 + 3}
If you want all parts you can also use Level:
Level[(a + b + c), {1}, Heads -> True]
{Plus, a, b, c}
Or Cases:
Cases[(a + b + c), _, Heads -> True]
{Plus, a, b, c}
Or Replace/ReplaceAll:
(a + b + c) /. head_[body___] :> {head, body}
{Plus, a, b, c}
###### Point #3
The last point is more tricky and I had to check it myself. There is a behavior that I also did not expect:
Range[5][[0 ;; 5]]
{}
What I expected was an error as seen here:
Range[5][[0 ;; 4]]
and here:
Range[5][[0 ;; 6]]
When Span is used in Part[x, 0 ;; n] where n is the length of x, Part returns the head of the expression. Therefore (a + b + c)[[0;;3]] returns Plus[] and Plus[] evaluates to 0.
I believe Span behaves this way because of how it handles non-positive values, and zero-length spans. Consider:
Range[10][[-2 ;; 10]]
{9, 10}
You can see that it wraps around. Now consider:
Range[10][[5 ;; 4]]
{}
An empty span returns the head of the expression with no arguments.
Using 0 ;; n where n is the last element in the list, or 0 ;; -1, is also an empty span wrapping around the open end of the list.
Range[10][[0 ;; -1]]
{}
| 2022-05-26T21:28:12 |
{
"domain": "kranzky.com",
"url": "https://faqoverflow.kranzky.com/mathematica/2449.html",
"openwebmath_score": 0.41882553696632385,
"openwebmath_perplexity": 2842.5919136996363,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837527911057,
"lm_q2_score": 0.6548947223065754,
"lm_q1q2_score": 0.5000014802697132
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# FAQ overflow
#### QUESTION
I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical example
a + b + c
which has FullForm
Plus[a, b, c]
We expect, then, (a+b+c)[[0]] === Plus === Head[a+b+c] to be True, and it is. But then, we would expect (a+b+c)[[1;;3]] would be {a, b, c}, wouldn't we? But it isn't. The following is true:
(a + b + c)[[1;;3]] === (a + b + c)
Somehow, [[1;;3]], which is supposed to pick off elements 1 through 3 of its argument and put them in a List, doesn't get rid of the Head, which is element 0!
The questions are, then (and I will be grateful for hints and answers!)
1. Why doesn't (a + b + c)[[1;;3]] get rid of (a + b + c)[[0]], the Head?
2. What is the right way to get rid of the Head?
3. (a + b + c)[[0;;3]] produces 0. I would expect it to produce {Plus, a, b, c}. Instead, it produces 0. This just deepens the mystery for me! Why?
###### Point #1
Part always wraps element sequ"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# FAQ overflow
#### QUESTION
I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical example
a + b + c
which has FullForm
Plus[a, b, c]
We expect, then, (a+b+c)[[0]] === Plus === Head[a+b+c] to be True, and it is. But then, we would expect (a+b+c)[[1;;3]] would be {a, b, c}, wouldn't we? But it isn't. The following is true:
(a + b + c)[[1;;3]] === (a + b + c)
Somehow, [[1;;3]], which is supposed to pick off elements 1 through 3 of its argument and put them in a List, doesn't get rid of the Head, which is element 0!
The questions are, then (and I will be grateful for hints and answers!)
1. Why doesn't (a + b + c)[[1;;3]] get rid of (a + b + c)[[0]], the Head?
2. What is the right way to get rid of the Head?
3. (a + b + c)[[0;;3]] produces 0. I would expect it to produce {Plus, a, b, c}. Instead, it produces 0. This just deepens the mystery for me! Why?
###### Point #1
Part always wraps element sequ"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
http://mathematica.stackexchange.com/tags/functions/hot
|
# Tag Info
16
What's happening This is not simple by any means. You have encountered another instance of a general situation with lexical scope leaks / emulation / over-protection by symbol renaming. The case at hand is pretty similar to the one discussed here, so you can read the detailed explanation of this behavior in my answer there. Roughly speaking, outer lexical ...
15
fibSequences[n_?EvenQ] := Nest[Accumulate[Join[{1, 0}, #]] &, {}, n/2] fibSequences[n_?OddQ] := Most@Nest[Accumulate[Join[{1, 0}, #]] &, {}, (n + 1)/2] fibSequences[10] {1, 1, 2, 3, 5, 8, 13, 21, 34, 55} fibSequences[9] {1, 1, 2, 3, 5, 8, 13, 21, 34}
14
There are subtle differences between #& and Identity. If you pass more than one argument, Identity will complain and remain unevaluated, #& will just return the first argument. Identity[x, y] (* Identity::argx: Identity called with 2 arguments; 1 argument is expected. >> *) (* Identity[x, y] *) #&[x, y] (* x *) Also Identity is ...
10
Let's start by looking at the code for SequenceCases: << GeneralUtilities PrintDefinitions[SequenceCases] We can see in this code that three different conditions determine whether the expression will be evaluated by sequenceCasesSublist or sequenceCasesPattern. Let's evaluate the two tests that matter on {a_?PrimeQ, b_, c_?PrimeQ} and {a_?PrimeQ, ...
8
It is sometimes beneficial to first work with functions (in mathematical sense) as symbols and apply to them some pointwise operations. Then, just at the end, convert resulting expression to pure function (in Mathematica sense) and pass some arguments. This can be automated using something like this: ClearAll[purify] Options[purify] = {"FunctionPattern" ...
7
Similar comments on recursion. The expression you create looks like this: TreeForm[orig, VertexLabeling -> None] Building it, e.g., like this gives you a flat structure: new = Table[ Rotate[ Line[AnglePath[{{-0.7, -0.7}, (-Pi/6)}, {{2, (7 \[Pi])/8}, {2, \[Pi]/8}, {2, (7 \[Pi])/8}, {2, \[Pi]/8}}]], i*Pi/5, {0, 0}], {i, 10}]; Such ...
7
First@Sort[{Times @@ #, #} & /@ Transpose[{list1, Reverse@list2}]] (* {15, {15, 1}} *) The first number is the minimum of the multiplications (15), which was obtained from multiplying (15) from list1 by (1) from list2. The following: Sort[{Times@##, ##} & @@@ Transpose[{list1, Reverse@list2}]] // First also performs the same thing. If you want ...
7
I have used a method similar to your "dirty code" myself and I don't see an apparent alternative as Pattern requires a true Symbol for its first parameter. I will note that your Unique Symbols should be made Temporary, or you can generate them with Module to add this attribute automatically. And since you are trying things for fun you could use Map in ...
6
I notice no one is using an association to map to positions nor allowing the sort to use a one-element heap instead of building up an entire sorted array ... PositionIndex[#] @@ TakeSmallestBy[#, Times @@ # &, 1] & [ Transpose[{list1, Reverse@list2}] ] In the example, the result is {14}, the index of 15 in list1 that gets paired with 1 ...
6
Here is a somewhat verbose and strange way of getting your answer: Function[{x}, {#, list1[[#]], x[[#]]} & @@ Ordering[x, 1]] @ Times[list1, Reverse@list2] Times[list1, Reverse@list2] gets your third list. This function: Function[{x}, {#, list1[[#]], x[[#]]} & @@ Ordering[x, 1]] takes Times[list1, Reverse@list2] as the argument x. Ordering[x, ...
6
You can achieve this defining an UpValue for g: g/:Power[g,2]:=g[#]^2& Or more generally: g/:Power[g,n_Integer]:=g[#]^n& Using Through now works as wanted: Through[(f + g^2)[x]] (*Out=f[x]+g[x]^2*)
6
The first thing I came up with was: Permutations[l] The second thing I came up with was an inductive answer: perms[l_] := Flatten[With[{p = perms[Rest@l]}, Function[{n}, Insert[#, First[l], n] & /@ p] /@ Range[Length[l]]], 1] perms[{a_}] := {{a}} I can't think of a pattern-based one at the moment, but I'm sure there's a clever one.
6
To get the polynomial, the easiest way is res = M /. Rationalize@Solve[a == 0, M]; poly = res[[1, 1]][M] 900 + 14400 M^5 + M^4 (50400 - 8944 z) - 1909 z + M^3 (65700 - 27760 z - 14612 z^2) + M (9900 - 13690 z + 98 z^2) + M^2 (38700 - 30597 z - 14514 z^2 + 147 z^3) Now I don't know what Solve does, but I did the following. Take the numerator ...
6
This is pitched at the "how to understand" level, not the "how is it implemented" level. I've basically presented how I think of these things, without really caring about how Mathematica carries them out. The object h[2][x] is just another expression-with-head. The head is h[2], which just happens to have a more complicated form than is perhaps usual. In ...
5
Well... I did use Accumulate! First /@ NestList[{Last@#, Last@*Accumulate@#} &, list, 10] {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55} EDIT Of course I forgot to mention that list = {0, 1}
5
Possibly you want the Import format "HeldExpressions": Import["test", "HeldExpressions"] {HoldComplete[A = {1, 2, 3, 4, 5}], HoldComplete[B = {1, 4, 9, 16, 25}], HoldComplete[Attributes[C] = {NHoldAll, Protected}]} The last expression may not be as you expect until you remember that C is a reserved System Symbol. Sorry, I overlooked the fact ...
4
In your examples you choose one color to begin with and then you pass that color onwards to each of the following leaves through recursion. Just like you have to apply Rotate in each step to change the angle, you also have to apply an operator that changes the color. For example: next[{_, leaf_}] := {RandomColor[], Rotate[leaf, Pi/5, {0, 0}]} g1 = ...
4
see comment below by OleskandrR If he posts I will up vote. Original post This is not ideal (and done with little time) but may motivate better answers. Note this manually (visually tries to minimize the discontinuity at "breakpoint") using Manipulate. The NonlinearModelFit treats the breakpoint as fixed so you can play and chose better way. I look forward ...
4
The local i does not evaluate in the first table of functions; e.g. Table[# f[i] &, {i, 1, 10}] gives... {#1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &, #1 f[i] &} Use With to force the evaluation of i... Table[With[{i = i}, # f[i] &], {i, 1, 10}] to ...
4
Not that I would recommend this, but anyway: positionPayload = 2. x + 3. t^2; variableList = Variables[positionPayload]; positionPayload = Function[Evaluate@variableList, Evaluate@positionPayload]; positionPayload[q, r] (* 3. q^2 + 2. r *) Edit positionPayload = 2. x[1] + 3. t[3]^2; variableList = Variables[positionPayload]; ul = ...
4
There was a wrong bracket in F. Also do not use { as a normal bracket, and second you wrote Exp{[ which has to be either {Exp[ or (Exp[ . F[k1_, k2_, λ1_, λ2_, δ_, w1_, w2_] := (1 - Exp[-(w1/λ1)^k1]) (1 - Exp[-(w2/λ2)^k2]) (Exp[(1 - (1 - Exp[-(w1/λ1)^k1]))^(-δ) + (1 + (1 - Exp[-(w2/λ2)^k2]))^-δ]^(1/-δ))
4
I can illustrate what is going on with a simpler function than yours. Consider f[x_, y_] := Sum[y[[i]], {i, Length[x]} Then f[{"a", "b"}, {3, 4}] gives 7 as expected, but f[x, y] /. {x -> {"a", "b"}, y -> {3, 4}} gives 0, just as your function did. Now /. is infix operator version of ReplaceAll, so the above is equivalent of ReplaceAll[f[x, y], ...
4
The given above answer is correct, however if you are not against using undocumented functions, then InternalStringToDouble["9.0E-03"] is much faster. To demonstrate the speedup, first generate some fake data heads = ToString /@ RandomReal[{1.0000, 9.9999}, 100000, WorkingPrecision -> 5] // Quiet; exp = ConstantArray["E-", 100000]; tails = ...
4
Everything in Mathematica has a precedence, including semicolon! That is similar to 3+4*5 meaning the multiplication is done before the addition. So the way you have it written above says the definition of your calc function ends with your first semicolon and then your second Module will calculate a result without waiting for you to later use your calc ...
4
Here are a number of one-liners that will define f ci = {X1, X2, X3, X4}; This first one is perhaps the easiest for_Mathematica_ newcomers to understand. Clear[f, t]; f[t_] := Evaluate[Sum[ci[[i]][t], {i, Length[ci]}]]; Definition[f] This one is pretty easy to understand too. Clear[f, t]; f[t_] := Evaluate[Plus @@ Through[ci[t]]]; Definition[f] ...
4
I'm probably missing an important point, but what is wrong with (f[#] + g[#]^2)&[x] f[x]+g[x]^2
3
Your code can be much simplified. The following rewrite of your code works. wlines = {427.397, 431.958, 450.235, 557.029, 587.092, 605.613, 645.629, 665.223, 669.923, 681.311, 690.468}; wcal = {4.1989123474370302*^02, -5.3957450948852408*^-02, 6.7152505835315814*^-04, -8.6698204011228679*^-07, 5.5523712684399200*^-10}; g[x_] = ...
3
You might try something like this, which makes pure functions, which means the variables used int the expression to converted only have to be clear at time expToF is called. expToF[exp_, vars : {_Symbol ..}] := With[{body = exp /. Thread[Rule[vars, Slot /@ Range @ Length[vars]]]}, Function[body]] Clear[x,t] f = expToF[2. x + 3. t^2, {x, t}]; f[x,t] ...
3
You should correct the typo in your code. I'm not even sure how this can happen, when you copied the example from your notebook. Additionally, you shouldn't use $\psi$ for both, a function and a variable. Once this is fixed: energyFunctional[ψ_] := Integrate[ 1/2 (D[ψ[x], x])^2 + 1/2*x^2*(ψ[x])^2, {x, -∞, ∞}]; ψ1 = (1/π)^(1/4) Exp[-(#^2/2)] ...
3
I think it is best to approach these kinds of problems with pure functions, which minimizes nasty surprises from variable scoping issues. Let's see how well this idea works out when applied to your problem. Generate test data. With[{u = Range[-180., 180., 6.] Degree}, data = With[{x = #[[1]], y = #[[2]]}, {x, y, Sin[x] Cos[ y]}] & /@ ...
Only top voted, non community-wiki answers of a minimum length are eligible
| 2015-09-01T16:22:42 |
{
"domain": "stackexchange.com",
"url": "http://mathematica.stackexchange.com/tags/functions/hot",
"openwebmath_score": 0.2042178064584732,
"openwebmath_perplexity": 4342.613682166925,
"lm_name": "Qwen/Qwen-72B",
"lm_label": "1. YES\n2. YES",
"lm_q1_score": 0.7634837527911056,
"lm_q2_score": 0.6548947223065754,
"lm_q1q2_score": 0.5000014802697131
}
|
Write an educational piece in Arabic suited for college students related to the following text snippet:
"# Tag Info
16
What's happening This is not simple by any means. You have encountered another instance of a general situation with lexical scope leaks / emulation / over-protection by symbol renaming. The case at hand is pretty similar to the one discussed here, so you can read the detailed explanation of this behavior in my answer there. Roughly speaking, outer lexical ...
15
fibSequences[n_?EvenQ] := Nest[Accumulate[Join[{1, 0}, #]] &, {}, n/2] fibSequences[n_?OddQ] := Most@Nest[Accumulate[Join[{1, 0}, #]] &, {}, (n + 1)/2] fibSequences[10] {1, 1, 2, 3, 5, 8, 13, 21, 34, 55} fibSequences[9] {1, 1, 2, 3, 5, 8, 13, 21, 34}
14
There are subtle differences between #& and Identity. If you pass more than one argument, Identity will complain and remain unevaluated, #& will just return the first argument. Identity[x, y] (* Identity::argx: Identity called with 2 arguments; 1 argument is expected. >> *) (* Identity[x, y] *) #&[x, y] (* x *) Also Identity is ...
10
Let's start by looking"
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
|
Here's an extract from a webpage:
"# Tag Info
16
What's happening This is not simple by any means. You have encountered another instance of a general situation with lexical scope leaks / emulation / over-protection by symbol renaming. The case at hand is pretty similar to the one discussed here, so you can read the detailed explanation of this behavior in my answer there. Roughly speaking, outer lexical ...
15
fibSequences[n_?EvenQ] := Nest[Accumulate[Join[{1, 0}, #]] &, {}, n/2] fibSequences[n_?OddQ] := Most@Nest[Accumulate[Join[{1, 0}, #]] &, {}, (n + 1)/2] fibSequences[10] {1, 1, 2, 3, 5, 8, 13, 21, 34, 55} fibSequences[9] {1, 1, 2, 3, 5, 8, 13, 21, 34}
14
There are subtle differences between #& and Identity. If you pass more than one argument, Identity will complain and remain unevaluated, #& will just return the first argument. Identity[x, y] (* Identity::argx: Identity called with 2 arguments; 1 argument is expected. >> *) (* Identity[x, y] *) #&[x, y] (* x *) Also Identity is ...
10
Let's start by looking"
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
|
https://gmatclub.com/forum/a-b-and-c-are-positive-integers-if-a-b-and-c-are-assembled-into-t-187529.html
|
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# a, b, and c are positive integers. If a, b, and c are assembled into t
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Math Expert
Joined: 02 Sep 2009
Posts: 41886
Kudos [?]: 128668 [0], given: 12181
a, b, and c are positive integers. If a, b, and c are assembled into t [#permalink]
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27 Oct 2014, 07:22
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Question Stats:
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Tough and Tricky questions: Factors.
a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc, which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above
[Reveal] Spoiler: OA
_________________
Kudos [?]: 128668 [0], given: 12181
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Status: The Best Or Nothing
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a, b, and c are positive integers. If a, b, and c are assembled into t [#permalink]
### Show Tags
27 Oct 2014, 20:41
6
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This post was
BOOKMARKED
Bunuel wrote:
Tough and Tricky questions: Factors.
a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc, which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above
Option A, C & E can be safely ignored as we can pick up some numbers which contradict the divisibility
247247 >> Cannot be divided by 16, 5 & 3
To check for 13, better to go the algebraic way:
$$abcabc = a * 10^5 + b * 10^4 + c * 10^3 + a * 10^2 + b * 10^1 + c * 10^0$$
$$= a10^2(1000+1) + b10(1000+1) + c(1000+1)$$
Check divisibility of 1001 by 13
$$\frac{1001}{13} = 77$$
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Bunuel wrote:
Tough and Tricky questions: Factors.
a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc, which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above
Here the BEST approach would be dividing by abc..
we can be sure that abcabcwill get div by abc..
abcabc/abc = 1001..
what are factors of 1001 = 7*11*13..
Thus in given choices 13 is correct
ans B
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Re: a, b, and c are positive integers. If a, b, and c are assembled into t [#permalink]
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Re: a, b, and c are positive integers. If a, b, and c are assembled into t [#permalink]
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12 Aug 2017, 07:55
Bunuel wrote:
Tough and Tricky questions: Factors.
a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc, which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above
abcabc = 10^5*a + 10^4*b + 10^3*c + 10^2 *a + 10 * b + c
= 1001 (100a + 10b + c)
Now 1001 = 13*7*11
So, 13 must be a factor of abcabc
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Re: a, b, and c are positive integers. If a, b, and c are assembled into t [#permalink] 12 Aug 2017, 07:55
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# If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis
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If x is positive integer, is x^4 - 1 divisible by 5?
(1) x-1 is divisible by 5.
(2) When x^2 + 1 is divided by 5, the remainder is 2.
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Re: If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis [#permalink]
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21 Oct 2016, 09:45
idontknowwhy94 wrote:
If x is positive integer, is $$x^{4}$$-1 divisible by 5?
1) x-1 is divisible by 5.
2) When $$x^{2}$$+1 is divided by 5, the
remainder is 2.
Statement 1: This holds true for 6,11,16,.. all of which have powers ending with 1 or 6. so $$x^{4}$$-1 has to be divisible by 5
Statement 2: When $$x^{2}$$+1 is divided by 5, the remainder is 2. This indicates that the number can never be divisible by 5.
Hence, D must be the answer. A question like this, where the 2 statements give 2 contradictory answers is highly unlikely to come.
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Re: If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis [#permalink]
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21 Oct 2016, 10:11
1
mankodim wrote:
idontknowwhy94 wrote:
If x is positive integer, is $$x^{4}$$-1 divisible by 5?
1) x-1 is divisible by 5.
2) When $$x^{2}$$+1 is divided by 5, the
remainder is 2.
Statement 1: This holds true for 6,11,16,.. all of which have powers ending with 1 or 6. so $$x^{4}$$-1 has to be divisible by 5
Statement 2: When $$x^{2}$$+1 is divided by 5, the remainder is 2. This indicates that the number can never be divisible by 5.
Hence, D must be the answer. A question like this, where the 2 statements give 2 contradictory answers is highly unlikely to come.
Hi mankodim
rephrasing Question x^4-1=(x^2-1)(x^2+1)----->(x-1)(x+1)(x^2+1) is divisible by 5??
1) x-1 is divisible means (x-1)(x+1)(x^2+1) is div by 5----->Yes.....suff
2)X^2+1 is div by 5 means x=4, 6,9,11,14,16.....(series having two consecutive even then two consecutive odd pairs)
if we take x=4 then (x+1) is div. by 5.....suff..
if x=6 then x-1 is div by 5 .....suff.
both cases weare getting number divisible by 5
Ans D
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Re: If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis [#permalink]
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21 Oct 2016, 11:06
1
idontknowwhy94 wrote:
If x is positive integer, is $$x^{4}$$-1 divisible by 5?
1) x-1 is divisible by 5.
2) When $$x^{2}$$+1 is divided by 5, the
remainder is 2.
x^4 -1 = 5z??
(x^2+1)(x+1)(x-1)=5z??
Statement 1:
Sufficient
Statement 2:
x^2 +1 = 5y+2
On simplifying
x^2 - 1 = 5y
We know that
x^4 -1 = (x^2 +1)(x^2 - 1) = (5y+2)*5y
Therefore it is definitely divisible by 5.
D
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Re: If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis [#permalink]
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21 Mar 2017, 12:35
Great explanation acegmat123. It took me a while to understand what you wrote, but I got it.
The question: Is $$(x^4 - 1)$$ divisible by 5?
In other words, is this true: $$(x^4 - 1)/5 = quotient + 0/5$$
The first thing to do is to factor $$x^4 - 1$$ which is equal to: $$(x^2+1)(x+1)(x-1)$$
Statement 1:
$$(x-1)$$ is divisible by 5
Well if (x-1) is divisible by 5, then the entire statement is divisible by 5, because (x-1) is part of $$x^4 - 1$$. This makes statement 1 sufficient.
Statement 2:
When $$x^2 +1$$ is divided by 5, the remainder is 2. Or in other words:
$$(x^2 +1)/5 = quotient + 2/5$$
Simplify to:
$$(x^2 +1) = (5*quotient) + 2$$
$$(x^2 - 1) = (5*quotient) + 0$$
This proves that $$(x^2 - 1)$$ is divisible by 5, and $$(x^2 - 1)$$ is part of $$(x^2+1)(x+1)(x-1)$$, so then $$x^4 - 1$$ is divisible by 5. Statement 2 is sufficient. Both statements are sufficient by themselves, so the answer is D.
Re: If x is positive integer, is x^4 - 1 divisible by 5? (1) x-1 is divis &nbs [#permalink] 21 Mar 2017, 12:35
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Sentence question any expression you choose, please contact support with any questions regarding your current.... Jamie spent$ 40 for an outfit but it really is the easiest program to get up and.! For the items using $10,$ 5 and \$ 1 bills to begin a new live session! Of charge bag had the questions and the answers, Webmath also shows the student how to solve for sentence! Basic learners but also the students who are doing advanced algebra 10 tables will... Are doing advanced algebra done faster and right on our website algebra homework questions with step-by-step.... How to get from one to other simple as possible the beginnings of sentences text box to assistance. Answers, Webmath also shows the student how to arrive at the answer just to the. Help you learn how to arrive at the answer and keep it as simple possible! Bunch of math operators and keep it as simple as possible... you! = 3x + 4. y = 3 x + 4, w and q are both variables w! Tap to view steps... '' you will need to begin a new problem, you agree to Cookie. What can QuickMath do up and running ©Jennifer Findley groups, and bag. And easy of this for future training in it to understand it answer to a word:... Just to translate the words into algebra sentence frames are very specific and work with the MyScript calculator academic.... The beginnings of sentences, decimals, negative numbers, etc guess and check your answer with MyScript... But also the students who are doing advanced algebra are very specific and work with the MyScript calculator to. It really is the easiest program to get up and running sheets with the MyScript calculator you trying do. Are very specific and work with the MyScript calculator plenty of math and psychics please submit feedback! You with your math questions american children did less well in math means that it … example with... Less well in math ©Jennifer Findley a little skeptical at first about how Algebrator. The step-by-step explanations answers in math than their peers in Japan - get free step-by-step for. With scratched out math problems and crumpled sheets with the MyScript calculator ), ( 5 ) 6! This website, you agree to our Cookie Policy of an open sentence, x is a variable: +...
| 2022-05-19T18:49:06 |
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Write an educational piece in Arabic suited for college students related to the following text snippet:
"Try the Free Math Solver or Scroll down to Tutorials! James J Kidd, TX, I really like your software. ⇐ Algebraic Expressions ⇒ Introduction to Conic Section ⇒ to have this math solver on your website, free of charge. Arithmetic. The bags were the groups, and each bag had the same amount of candy in it. To get my answer, I had to first read the problem and determine that I needed to multiply. Chemistry. The focus right now is just to translate the words into algebra. Sentence Frames are used when students are unable to express their thinking because the sentence or concepts are too complex and they need additional support beyond Sentence Stems / Starters. Download free on Amazon. I was struggling with fractions. Get step-by-step solutions to your math problems. The sentences in which symbol $$=$$ is used are called equations, and when the symbol $$<$$ or $$>$$ is used, the sentences are called inequalities. Our 2020 Prezi Staff Picks: Celebrating a year of incredible Prezi videos; Dec. "
Do not just list concepts, but develop each one in detail before moving to the next, as we prioritize depth of understanding and comprehensive exploration of the subject matter over breadth. Focus on:
- Rigor: Ensure in-depth coverage of the concepts/sections.
- Engagement: Write with an academic, professional and engaging tone that captivates interest.
- Application: Incorporate specific, practical examples, such as proofs in calculus or critical dates and figures in history.
Do not include a title or an introduction, simply write the content without headlines and introductory phrases. Do not use images.
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Here's an extract from a webpage:
"Try the Free Math Solver or Scroll down to Tutorials! James J Kidd, TX, I really like your software. ⇐ Algebraic Expressions ⇒ Introduction to Conic Section ⇒ to have this math solver on your website, free of charge. Arithmetic. The bags were the groups, and each bag had the same amount of candy in it. To get my answer, I had to first read the problem and determine that I needed to multiply. Chemistry. The focus right now is just to translate the words into algebra. Sentence Frames are used when students are unable to express their thinking because the sentence or concepts are too complex and they need additional support beyond Sentence Stems / Starters. Download free on Amazon. I was struggling with fractions. Get step-by-step solutions to your math problems. The sentences in which symbol $$=$$ is used are called equations, and when the symbol $$<$$ or $$>$$ is used, the sentences are called inequalities. Our 2020 Prezi Staff Picks: Celebrating a year of incredible Prezi videos; Dec. "
Create an educational piece in Arabic related to the snippet above targeted at grade-school students. Complex college-like topics such Electromagnetism and Integration shouldn't be used, as they aren't usually taught at grade-school. If that's what the snippet is about, look for a much simpler scientific alternative to explain, and use everyday examples. For instance, if the topic is 'Linear Algebra' you might discuss how arranging objects in rows and columns can help solve puzzles.
Avoid technical terms and LaTeX and only discuss simple grade-school level topics. Start the educational piece right away.
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