1) If u(r,\theta,\phi)=\frac{1}{r}, is \frac{\partial{u}}{\partial {\theta}}=\frac{\partial{u}}{\partial {\phi}}=0 because u is independent of \theta and \;\phi?
2) If u(r,\theta,\phi)=\frac{1}{r}, is:
\nabla^2u(r,\theta,\phi)=\frac{\partial^2{u}}{\partial...