Applied Mathematics

Sir, What are the applications of Eigen values and Eigen vectors in Electrical and Electronics field ? Please explain.... Thanking you.

Does anyone know links to forums (similar like this) for using Lingo (Lindo) modeling or optimization, math modeling, computer science algorithms? Thanks.

I decided to go over the probability section in my S1 statistics book. However, it seems i've stumbled at the first hurdle. The first exercise is about the addition rule P(AUB) = P(A) + P(B) - P(AnB). There is a question where it asks about the probabilities events not happening, P(A'), P(A'UB), P(A'nB') etc. I know that P(A') = 1 - P(A), but i'm completely stuck on how to get such probabilities of P(A'nB). Can anyone help unclog my mental block? Thanks once again, Rob

Can someone explain what this example is trying to say? How was 1/(n+1) obtained?

i usually have the window and door closed... when i get out of my room i have to do some effort to close the door (e.g. pushing a bit). (and for close it when i come back)... if i open the window the door is easy to close. i think that it should be a "decompressing" of the room of some like that... i don't know if it has more pressure after i open the window or before... my guess is that there are more pressure when is all closed because i use t-shirt all time inside the room and i don't use any sort of heat-device (and here is winter)... i mean... using P=nkT/V (V is constant)... but i'm not sure...

For the sample y: 2 3 4 4 6 6 7 8 9 11 What is the first and third quartile? My notes say it's 4 and 8.25 respectively, but my brother says it's 4 and 8.

if anyone has any clues on this other question that has been puzzling me any help would be greatly appreciated! * someone who runs a correlational analysis says that an effect size of 64% has been found. What value of Pearson's r did they obtain? 1) +0.8 2) -0.8 3) 0.8, we cannot tell whether the value is positive or negative 4) +0.64 5) none of the above

Anyone could explain me in what sense the sigma field in a probability space are related with the information that we have (any example?) (i have listen about: sigma field with more sets could be interpretated like we have more information, but I don't understand the idea yet) P.S: obviously my english is very bad

Statistically speaking, if something happens somewhere, there should be a lower chance of it happening right? For example, after that big earthquake in Osaka some years ago, Osaka would probably pretty safe to visit, because you wouldn't expect another big Earthquake. Similary, if a place has been terrorist bombed, then immediately following the incident, the place should be very safe. (although there was plans for a second attack, but it failed - because it wasn't statistically viable yet ) Would any of you hesitate to go to London today?

So yeah, was just thinking about this on a bus. Suppose you have a bus length l and a suicide bomber intent to kill as many people as he/her can. Assume the position where the bomber sits/stands has pdf 1/l (inside the bus). Also take injury/death which has a strictly decreasing pdf symmetrical around the bomber (like the bell curve or something linear, does it matter?). What is the safest place to be in the bus?[minimise the prob of death/injury] Does it even exist? The solution is probably trivial or something, but I cannot think of an intuitive answer

I must solve A*(Uxx+Uyy)-B(x)*Ux=0 , where Uxx means ssecond partial derivative of U on x and U(x,y); Ais constant and B(x) is function of x! The eq has BC dU/dz=0 and dU/dy=0 IC U(0,y)=1 for -1<y<0 and U(0,y)=1 for 0<y<1 in Mathematica! Can anybody help me with some example? Thanks, Jan mail: jan_golob@email.si

How do you prove that AD * AC = AB^2?

I've forgotten nearly everything in geometry, so I'm having trouble with this problem. Imagine you have a triangle ABC. The midpoints of the line segments are D, E, and F. Prove that the quadrilateral ADFE is a parallelogram.

The question is simple why is it 360 deg in a circle and not a number that is easier to work with. More importantly were does the number "360" come from when was it chosen why was it chosen and by who? P.S. What other units of mesurement are used to mesure angle?

Why aren't rationals suspect to Cantor's diagonal proof? That is, can anyone give a proof that they aren't suspect? And can you try to prove this without taking the method of proving that they are countable first? Let's just take rationals between 0 and 1 in binary to simplify things this way. Cantor's diagonal proof for the real numbers goes as follows: Proven: The real numbers between 0 and 1 are uncountable (they have no one-to-one correspondence with the integers). Proof: Let us assume the real numbers between 0 and 1 are countable. Then write them down in any order in a table. Put them in binary for simplicity. Then, take the 1st number after the decimal…

Could someone please help me with this question? I've had a go, but I don't really understand it. A block of mass 3kg is at rest on a rough horizontal plane. The block is acted on by a horizontal force of magnitude 14.7N. Given that the block is on the point of sliding, find the coefficient of friction between the block and the plane. Friction = coefficient of friction x normal reaction 14.7 = coefficient x (3 x 9.8) 14.7 = coefficient x 29.4 Coefficient of friction = 0.5 The horizontal force is now replaced by a force of magnitude P N acting downards at 30º to the horizontal. Given that the block is again on the point of sliding, find the value of …

I want to find the correlation between 2 sets of measurements. The range of the observed values is between -1.5 and 1.5. Now in theory, the values could be between -6 and 6 (but this is less likely to be). I also know that the 2 sets should have a high correlation (both sets are measurements of the same thing, but it has been measured with 2 different machines). Right now, I don't get a very high correlation (around 0.4). I know that if I increase the range of the observed data, it should help raise the correlation. But it is difficult to do so experimentally. So I thought that a correction to the correlation might help. I read on the Internet that low reliability at…

This is a branch from another thread. Matt, it's been a long time since I've used poles and residues. I remember the method of images, and some other things here and there, but its been a long time. One question.... What is a meromorphic function, and how does it tie into the concept of infinity? Ok, analytic functions. That was the entire first half of complex variables. Analytic functions. As I recall, a function is analytic at a point, if it's differentiable there?

Does it go on forever approaching zero, or is it just zero?

When I was a child no one taught me it was a language unto itself. I understand when a mathematician writes a book he sees the world from a mathematical perpective. Yet when a philosopher does the same its the same principle. I am fasinated with algebra. To me its like analytical philosophy only with words. I understand one plus one better than 1+1. We both arrive at the same answer but from different perspectives. Can we judge both perspectives wrong? pljames

this is a vitally important question! any hints?

hey, just double checking this stuff (i have only just begun this topic in maths and so i am a little shaky on it) is the answer to this: i) no , because the zero vector is not in the set H. ii) yes, but i don't know how to explain why, i guess if you let s and t be zero, then the zero vector is part of the set L , and obviously if you add any two vectors it will still be in L and if you multiple by a scalar it will be too... anyways, yeah as i said, i'm a greenhorn with this stuff, so take pity Sarah

hey just wanted to know if my answer is good?...thanks guys my answer would be X = A°(C - D) - B° where "A°" stands for inverse of matrix A ...etc...

i cant figure out this question. N people playing a game, and X_i is the score of the ith person. assume X_i are independent with density f(x)=2x for 0<x<1; and f(x)=0 otherwise. High score wins. What is the expected value of the winner's score? thanks in advance

I haven't been in the forum in ages so I thought I'd say hi (not that anyone rembers me ) I got into a discussion about the BT paradox and I was wondering what would happen if we converted the paradox from Euclidean space to Minkowski space. Ideas?