2. Let r = Vx2 + y2 + z2. (a) For n > 1 and r > 0, express V(run) in terms of r and the radial vector field er. (b) For r > 0, express V.Inr in terms of r and the radial vector field er. (c) Taking A as in question 1, show that for r > 0 we have A(r-1) = 0