Talk:QB/c19ElectricPotentialField SurfaceIntegral

Calculating $$\int f dA $$ and $$\int f dV$$ with angular symmetry Cyndrical: $$dA=2\pi r\,dz;\, dV=dA\,dr$$. Spherical: $$\int dA=4\pi r^2,\; dV=4\pi r^2\,dr$$