One-Dimensional Heat Equation Problem

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SUMMARY

The forum discussion focuses on solving the one-dimensional heat equation given by the partial differential equation \(\partial u / \partial t = k (\partial^2 u / \partial x^2) - 2u\) with boundary conditions \(u(0,t)=e^{-2t}\) and \(u(1,t)=0\). The initial condition is \(u(x,0)=e^{-x}\). Participants emphasize the importance of using the method of separation of variables, suggesting the substitution \(u(x,t) = X(x)T(t)\) to facilitate the solution process. The discussion also clarifies that the term "-2u" is present in the equation and guides the user to divide through by \(XT\) to proceed with the separation.

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HansLee
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Hi, I need help to solve this problem, about 1-D heat equation

\partialu / \partialt = k (\partial2u / \partialx2)-2u (0< x <1)

u(x,0)=e-x
u(0,t)=e-2t
u(1,t)=0

I need to solve it with separation variable
 
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Ok... what have you done so far? Do you know how to start a problem like this?
 
No, I have no idea how to start it, bcos it's non-homogeneous eq, can u help me?
 
I just realized that you don't actually have the heat equation in your first post. There should be no -2u term in the equation. Can you verify what you're supposed to be solving?

If you're actually trying to solve the heat equation, then start with u(x,t) = X(x)T(t) for some X and T functions and then try to separate the x's and the t's
 
Even with the "-2u" term, do exactly what Office Shredder says, just what you would normally do to "separate variables"- let u(x,t)= X(x)T(t) and put into the equation:

X\frac{du}{dt}= \kappa T\frac{d^2X}{dx^2}- 2XT

divided through by XT and see what happens.
 

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