Non-homogeneous wave equation on a cone

The wave equation ?tt?c2?xu(x,t)=e?tf(x,t) in the cone {(x,t):?x??t,x?Rd,t?R+} is shown to have a unique solution if u and its partial derivatives x are L2(e?t) on cone, can be explicit given Fourier series of orthogonal polynomials cone. This provides particular for boundary value problems non-homogeneous which combined with homogeneous obtain full solution.