Question 4 (15 points) Parts (a) and (b) are distinct from each other. (a) Find the surface area of the part of the hyperbolic paraboloid z = 5 + x2 - y that lies within the cylinder x2 + 2 = 4. (b) Find the maximum and minimum values of f(x, y) = 4x + 4y - x2 - y2 subject to the constraint g(x, y) = x2 + yz = 2