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Topic: Problem in Fourier series and Pdes
Replies: 4   Last Post: Nov 11, 2011 9:58 PM

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MTBrenneman@gmail.com

Posts: 983
Registered: 8/21/06
Problem in Fourier series and Pdes
Posted: Nov 11, 2011 9:31 AM
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Hi,

I am working on a problem from Churchill and Brown "Fourier series and
PDEs", 7th ed.

Problem is to solve the heat eqn:
(i) U_t = k * U_x,x -inf<x<+inf, t>0

Given the initial temp distbn:
f(x) = 1 if x>0, 0 if x<0

I work through the problem and get the soln:
U(x,t) = 1/2 * (1 - Erf[ x / (2*sqrt(k*t)] ) for t>0
the book gets the same soln but has a plus sign between the two terms.

Does anyone know offhand which soln is correct or if the book is in
error on this problem. I've gone through it several times and cannot
find an error on my part.

Thanks,
Matt



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