3. Cone r(u, v) [11 cos v, u sin v, cu] 4. Elliptic cylinder r(u, v) = [a cos v, b sin v, 11] 3. Cone r(u, v) [11 cos v, u sin v, cu] 4. Elliptic cylinder r(u, v) = [a cos v, b sin v, 11]