The problem is stated here:

A homogeneous body occupying the solid region D is completely insulated. Its initial temperature is f(x). Find the steady-state temperature that it reaches after a long time. (Hint: No heat is gained or lost)

Now, it was asked many months ago:

Working with initial and boundary conditions in PDEs | MathFax.com

However, it's no longer on mathhelpforum and the solution there doesn't have the math expressions any more.

Can any one tell me how to solve it?

All I have now is:

du/dn = 0

u(x, 0) = f(x)

u_t = k*u_xx

Intuitively though, I think the solution is a constant.

please help

thanks