Hey there! I'm faced with this problem: http://img7.imageshack.us/img7/4381/25686658nz9.png [Broken] It's a 1D nonhomogeneous wave equation with a "right hand side" equaling to the dirac delta function in x * a sinusoidal function in t. I have to find its general solution with the constraints: http://img177.imageshack.us/img177/8083/38983002rq3.png [Broken] I know that the solution, by D'Alembert's theorem, is equal to a double integral over the external function. I showed this in the original problem. I don't have a lot of experience with the dirac delta function. I know that integrals over [a,b] of the diract delta function = 1 if 0 is an element of [a,b]. The integral is 0 otherwise. I tried switching the order of integration. Didn't help much. I don't think that integration by parts helps, either. Can somebody point me in the right direction? Thanks!