Describe the surface x2 y2 2 sin z2 in general if fz 0

Question

Question: 1. Describe in words the level surfaces of the function g(x, y, z) = x + y + z.

2. Describe in words the level surfaces of f(x, y, z) = sin(x + y + z).

3. Describe the surface x² + y² = (2 + sin z)². In general, if f(z) ≥ 0 for all z, describe the surface x² + y² = (f(z))².