d(1, y, z) 3. Let z=rcos(0) sin(o), y = r sin(0) sin(6) and z = r cos(o). Calculate the Jacobian d(r, 0, 0) 4. Consider the following two equations in terms of the variables x, y and z: 2 x+2y+322-2xy = 0, (ax+6y) sin(z) + 23 = 0. (a) Under what conditions can x and y be considered functions of z? (b) What value(s) of a will prevent rx and y from ever being considered functions of z?