Hello!

I've been given a question on an assignment and I'm not quite sure where to start. It's supposed to be one of the harder questions, and I'm really unsure what I'm doing with it!

We're supposed to derive the Heat Diffusion equation ($\displaystyle u_{t} = ku_{xx}$) using Gauss' Divergence Theorem, which is (as you probably know if you're reading this!):

$\displaystyle \iiint_{V} (\nabla \cdot \textbf{F}) \enspace dV = \iint_{S} \textbf{F} \cdot \textbf{n} \enspace dS$

Any help would be much appreciated!

-Geo