1) Show that using the expressions for V and = in Cartesian coordinates. ) Use result from (a), the product rule for divergence, V. (f) = (f) +f(VF), an the chain rule for gradient, Vf (g) =g, to show that dg df (r) 2f(r) V. (f(r) f) = + dr r for a function f of r (the magnitude of 7). Hint: Let g()=r and recall from class that Vr = f.