Can someone help me with this, it's slightly different from other separable equation PDE's I've done before:

Consider a thin rectangular plate (0 <= x <= pi, 0 <= y <= pi/2) with the following steady-state temperature distributions on the edges

u(x,0) = 0

u(0,y) = 0

u(pi,y) = 0

u(x, pi/2) = 60sinx + 20sin2x

Find u(x,t) to determine the rate of change.

Thank you very much for any help. It's greatly appreciated.