Help!!! Show work please!!

Suppose that f (x, y, z) is a smooth function. (a) Show that curl Vf = 0 and div Vf = Af, where the Laplacian 22 22 22 A = + dy2 + 22 . (b) Show that div (fVg) = Vf . Vg+ fAg. 2. Letr = Vx2+y2+ z2. (a) For n > 1 and r > 0, express V(r-") in terms of r and the radial vector field er. (b) Forr > 0, express VInr 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-]) = 0. . Find the length of the part of the curve y = COIN 5x2 between x = 1 and x = 2