Consider a cylindrical wall with inside radius $r_1$ an outside radius $r_2.$ The inside surface is heated uniformly at a rate of $q_1\frac{W}{m^2},$ and the outside surface dissipates heat by convection with the heat transfer coefficient of $h_2\frac{W}{m^2}C$ into the ambient air at zero temperature. Write the governing heat equation and the boundary conditions for the boundaries at $r=r_1$ and $r=r_2.$