what is your idea about the quadric surface?

Question

anonymous · Answer

A quadratic surface intersects every plane in a (proper or degenerate) conic section. In addition, the cone consisting of all tangents from a fixed point to a quadratic surface cuts every plane in a conic section, and the points of contact of this cone with the surface form a conic section 

Examples of quadratic surfaces include the cone, cylinder, ellipsoid, elliptic cone, elliptic cylinder, elliptic hyperboloid, elliptic paraboloid, hyperbolic cylinder, hyperbolic paraboloid, paraboloid, sphere, and spheroid.

anonymous · Answer

can you give example of that

anonymous · Answer

we all know that the graph of a second degree equation is called the quadric surface.

anonymous · Answer

Sphere: