Tan_plane: Tangent Plane Expression & Display

Calculates the tangent plane of a Surface at point Xo and plots the surface, plane and Xo!

What it does?: You give it a surface (explicit, parametric or implicit form) and a point on it and you'll get the equation of the tangent plane (in the same form as the surface is) at that point and besides you'll see the surface, the plane and the tangential point Xo.
See <help tan_plane> for usage.
Useful for educational purposes or just for fun! ;)

Enjoy it ...!