Recent content by strangequark

Ok, I know there has probably been a vast number of posts exactly like this one, but... I'm a senior undergrad at a california state university and will be applying to grad school this semester. Preferably I want to get into a PhD program in computational biophysics, specifically I'm...

damn, I see what you're saying. Thanks for your help! I emailed the author of the paper in hopes that he can shed some light on how he obtained his solution.

All right, everything you guys said makes sense, especially getting rid of one of the constants. But, I'm trying to apply this to a physical situation, so I need to find a way to get rid of the constants. There is nothing in the region of interest [0,L] at t=0, but at t>0, material diffuses thru...

Hey all, I'm wondering if someone can help me understand how to apply the boundary conditions to the diffusion equation in one dimension. Diffusion equation is: \frac{\partial u}{\partial t}=D*\frac{(\partial)^{2}u}{\partial x^{2}} The initial condition is: u(x,0)=0 And the boundary...

Homework Statement Suppose that \phi is a homomorphism from a finite group G onto G' and that G' has an element (g') of order n. Prove that G has an element of order n. Homework Equations for a homomorphism, 1) \phi(a*b)=\phi(a)*\phi(b) 2) \phi(a^{n})=(\phi(a))^{n} 3)...

Homework Statement Hi, I'm having some problem with one of my final exam study questions, and I'm hoping someone can help me out a little. here is the problem: Let Y_{1},Y_{2},...,Y_{n} denote random samples of numbers from a uniform distribution on the interval [0,1]. Denote the...

Homework Statement Let X represent the random choice of a real number on the interval [-1,1] which has a uniform distribution such that the probability density function isf_{X}(x)=\frac{1}{2} when -1\leqx\leq1. Let Y=X^{2} a. Find the cumulative distribution F_{Y}(y) b. the density function...

Homework Statement A beam of \alpha-particles, of kinetic energy 5.3 MeV and intensity 10^{4} particle/sec, is incident normally on gold foil with thinckness 1 x 10^{-5} cm. (The density, atomic weight and atomic number of gold are 19.3 g/cm, 197 and 79 respectively.) A particle counter of...

Homework Statement The fraction of 6.0 MeV protons scattered by thin gold foil, of density \rho=19.3 g/cm^{3}, from the incident beam into a region where scattering angles exceed 60 degrees is equal to 2.0 x 10^{-5} . Calculate the thickness of the gold foil using the result of the previous...

I'm thinking that because f(z)=z^{i} is entire, and that the region in which the curve lies will be simply connected... then the anitderiv exists and since i is just a constant, then the primitive of f(z) will be F(z)=\frac{z^{i+1}}{i+1}... does anyone have any ideas? I'm really stuck here...

Homework Statement Compute the following integrals using the principle value of z^{i} a. \int z^{i} dz where \gamma_{1}(t)=e^{it} and \frac{-\pi}{2}\leq t \leq \frac{\pi}{2} b. \int z^{i} dz where \gamma_{1}(t)=e^{it} and \frac{\pi}{2}\leq t \leq \frac{3\pi}{2} Homework...

ok, nevermind, I think I got it... x_{avg}=\int^{\infty}_{0}x \sigma \rho e^{\sigma \rho} dx (i think)

Homework Statement Show that the attenuation length, \Lambda, is just equal to the average distance a photon travels before being scattered or absorbed. Homework Equations my book gives: number of photons absorbed = \sigma\rho I(x) dx number of photons present after a thickness x...

A grad student mentioned the other day that you cannot move a limit inside of an integral without meeting certain conditions, unfortunately, he didnt say what those condition were... I was under the impression that this was unrestricted (and the particular theorem we were looking at worked fine...

Homework Statement Let \gamma_{r} be the circle centered at 2i with a radius r. Compute: \oint \frac{f(z)}{z^{2}+1}dz Homework Equations 2 \pi i f(w)=\oint \frac{f(z)}{z-w}dz Cauchy's integral formula... maybe? The Attempt at a Solution I can see how to find solutions...