Recent content by Glass

So I'm confused on how we know we need x many BC and/or IC. For example, regarding the heat equation, we need 2 BC, and 1 IC (supposedly because there are two spatial derivatives and one time derivative). And similarly, for the Wave equation we need 2 BC and 2 IC. And another thing, why is it...

Homework Statement If F is a finite field show that there is a prime p s.t. (p times)a+a+...+a=0 for all a in the field Homework Equations The Attempt at a Solution Well I managed to prove that there must be an a in F s.t. (prime number, call p, times)a+a+...+a=0 but I can't seem...

Homework Statement Prove that if a is a 0 divisor of some ring, then for any b of the ring, ax=b cannot have one x that satisfies the equation (i.e. cannot have one solution) Homework Equations The Attempt at a Solution It seems to me this isn't even right. Say a is a right 0...

Ok thanks. But what happened to the energy? Did it radiate as heat or something?

Homework Statement I have a 1g object on a frictionless surface being hit with light of a frequency 632nm (directly parrallel to the surface and the object absorbs all the light). How many photons did the object absorb by the time it's moving at 1mm/s? Homework Equations The Attempt...

Thanks for the reply. But even after doing that, I still can't seem to make a pdf, ps, etc. When I try to go to quick build I always get one of two errors: 1) "Log File not found!" 2) "Could not start the command." Any ideas on what I'm doing wrong and how to fix it?

Hi, I understand how to use LATEX on this forum, but I was hoping to learn how to write actual documents using it. I have Texmaker installed on my computer (if there's a better editor, do tell), and I have no idea how to create a pdf or document or whatever I can create with this program...

I would do exactly as you suggested - solve for y2 in terms of y1 and sub back in. You will get a 2nd order ODE, but it is not too difficult. Moreover, if your unsure about the answer, you can always plug your solution back into the equation to ensure your solution satisfies the DE (although...

I would try partial fractions over the complex numbers. BTW, I've never actually done it, but see no reason why it couldn't be done. On the other hand, you may as well give it a shot while you wait for someone more qualified to answer.

I can't see your picture unfortunately.

From the definition of mgf I have: M(t) = \int_{0}^{1}e^{xt}3x^2dx Then after some integration by parts (or using a symbolic integrator) I get: M(t) = e^t(\frac{3}{t} - \frac{6}{t^2} + \frac{6}{t^3}) - \frac{6}{t^3} Then if we differentiate that twice (or even once or zero times) there...

Isn't it just a circle on the plane z=3? Or am I missing something?

I'm given the probability density function: f(x) = 3x^2 for x in [0, 1] f(x) = 0 elsewhere I want to find E[X^2] which is easy if I use the integral definition (I got 3/5). Yet, when I try and do this using Moment Generating Function (mgf) I cannot seem to get the same answer (in...

Wait nevermind, I got it.

Homework Statement Given a square with side lengths X, where X is a random variable with some probability density function (the actual pdf is not important for my question). Why isn't the expected value of the area = E[X]^2 = E[X^2]? Homework Equations The Attempt at a Solution...