I want help on converting differential operators such as the reduced wave operator (L=Δ+c) and the biharmonic operator (L=Δ^2) from Cartesian to spherical coordinates in n-dimensions.
For example I want to understand how I can derive the Laplace operator in spherical coordinates from the Laplace operator in n-dimensional Cartesian coordinates for solutions of the Laplace equation with spherical symmetry.
If it makes things easier, in all cases I want solutions of differentials with spherical symmetry.