6. (5 points) Let S be the part of the cone given by r(u, v) = (u cos v, u sin v, u) with 1 ≤ u≤ 2 and

0 ≤ ≤, oriented with downward pointing normals. Let F(r(u, v)) = (u cos v, u sin v, 2). Calculate

the flux integral

F

F. ds.