
Aime F. answered 12/04/22
Experienced University Professor of Mathematics & Data Science
On the paraboloid, dS = ndxdy where the outward unit normal n is in the direction of ∇(x² – y + z²) = 2xi – j – 2zk. On the disk, dS = ndxdz where n = j. That should get you most of the way to the solution.