Tangent Plane:

The tangent space at a point p of a surface is the set of all vectors tangent at p to curves on the surface passing through p. In general this space will be 2-dimensional, and in this case, it is called the tangent plane to the surface at the point p.

For a surface given parametrically, the tangent plane usually can be computed by computing the tangents to the parametric curves through the point p and (if they are not parallel) using these as generators for the plane.

8/12/94 dpvc@geom.umn.edu -- The Geometry Center