Consider the following code:
Integrate[F[t]*DiracDelta[(x - c)*(y - d)]*Sin[(Pi*m*x)/a]*Sin[(Pi*n*y)/b], {x, 0, a}, {y, 0, b}, Assumptions -> Element[{a, b, c, d}, Reals]]
I need to do the calculation on, but not the results, Hope everyone help.
What result did you get? What is wrong with it?