C. p. 1 if z = f(a(s, t), b(s, t)) = in a cos with a(s, t) = 28 +t and b(s, t) = 8 - 2t, find the first derivatives of z with respect to the independent variables s and t. c. p. 2 if w = f(s, t) with 8 = 8(x, y,z, p) and t = (x, y, z, p), write chain rule expressions for all possible first derivatives of w with respect to the four independent variables.