Determine how the
graph of the surface s(u, v) differs from the graph of r(u, v) =
u cos vi + u sin vj + u²k (see figure), where 0 ≤ u ≤ 2 and
0 ≤ y ≤ 2π. (It is not necessary to graph s.)

s(u, v) = u cos vi + u sin vj - uk 0 u 2, 0 y 2