x^2+y^2= 1,z= 1。

This curve is a circle (0,0, 1), where the radius is 1.

So the area s = π r 2 = π.

The surface obtained by parabola rotation 180. Mathematical parabola is a set of points whose distance to a fixed point (focus) on the same plane is equal to the distance to a fixed line (directrix).

Extended data:

When a = b, a surface is called a paraboloid of revolution, which can be formed by a parabola rotating around its axis. It is in the shape of a parabolic reflector. When the light source is focused, it will form a parallel beam after specular reflection. or vice versa, Dallas to the auditorium After the parallel beam shines on the mirror, it will be focused.

It is widely used in lights, flashlights and radars. Their reflecting surfaces are paraboloids.