(a) Suppose f(x, y) = f(r cos 0,r sin 0) = g(r, 0) and assume that all their partial derivatives are continuous. Show that (i) (ii) (V.V) f = V.Vf= V.Vf= v=10 (13) + 71 200 ag rr r (iii) Find the terms A(r), B(r), C(r) and D(r) such that 0g 20g 1 8g 1 ag r4 r r r +A(r); + B(r) + afaf + x dy - r r Jg r20 + 8g r0 g 204 + C(r). + D(r) (3 marks) (6 marks) 8g 20 (6 marks)