Chapter 13.3, Problem 3P

In the initial steady state of an infinite slab of thickness $l$, the face $x=0$ is at $0^{°}$ and the face $x=l$ is at ${100}^{°}.$ From $t=0$ on, the $x=0$ face is held at ${100}^{°}$ and the $x=l$ face at $0^{°}.$ Find the temperature distribution at time $t$.