# PDE problem : diffusion equation! help!

by sarahisme
Tags: diffusion, equation
 P: 64 Hi all, I am stuggling with this question ... so far i have only tried part (a), but since i can't see how to do that so far... :( ok so what to do... do we first look at an 'associated problem' ? ... something like lol, this stuff is all quite confusing -Sarah
 P: 64 hmm ok i tryed some more and i come up with this answer: however i don't know how to simplify it from here, i have looked up integral tables and still no luck. any suggestions guys? lol assuming the answer is right in the first place! :P cheers -sarah
 P: 1,439 i think you can solve these by separation of variables that is assume u(x,t) is a product of two functions - one which depends on x, and one which depends on t maybe something like this u(x,t) = F(x) G(t) and solve from there your text should give a description of doing such a problem...
 P: 64 PDE problem : diffusion equation! help! hmm i can't seem to get seperation of variables to work... what do you reckon for part (b)?
 P: 1,157 For part (b), you need to reduce the nonhomogenous boundary condition problem to a homogeneous one.
P: 64
 Quote by J77 For part (b), you need to reduce the nonhomogenous boundary condition problem to a homogeneous one.
ok, that sounds like a good idea.... but how do i go about doing that ? a hint please ;)

also, what do you think of my answer for part (a)?
 P: 64 hmm ok let me see.. what about if we let w(x,t) = exp(-x) then u(x,t) = w(x,t) + v(x,t) then v(x,t) satifies: so then we have to solve that pde problem? :S
 P: 64 its cool guys i worked it out! :D yay

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