Find the flux Fn ds for F=. Note: here F and n are vectors.

(a)Plane z=x-y inside the cylinder x²+y²=1

(b)Plane z=3x+4y above the square 0

These are the questions, the key to these problems is to find the normal vectors. But, it seems I find the wrong one so that I got 0 for both the questions!

Please explain how you parameterize to get the normal vector n.

Thanks in advance:)