Question

The circle (x−1)^2 +y^2 = 1,z = 0 lies inside the sphere centred at the origin, andhaving radius 2√2. Is it true or false ?

Answer 1

True.

For the circle the farthest point from the center of the sphere is (2, 0, 0), length from center = 2. The radius of the sphere is greater than 2, that's why the circle lies inside the sphere. Given the equation z=0, the part where z=0 is considered.