Okay what am I doing wrong here? It's an examination of the simple 1-d heat diffusion equation in a rod with homogenous boundary conditions. I'm looking for the temperature distribution over a thin rod with unit length 1. Both ends are held at 0. And the initial temperature distribution across the rod I have set equal to x, with the diffusivity k=1/10.
So first set up the 1-d homogeneous heat equation
he:=diff(u(x,t),t)=k*diff(u(x,t),t,t):