Tangents to curves in the plane: tangent

See Section 14.6.3 for tangents in space.

The tangent command finds tangents to curves.

tangent takes one or two arguments:
- C, a curve.
- p, a point.
or
- e, a point defined with element (see Section 13.6.15) using a curve and parameter value.

tangent(C,p) (or tangent(e)) returns and draws the list of lines tangent to the curve passing through the given point.

Examples.

Input:
tangent(circle(0,1),1+i)
Output:
Input:
t:= element(0..pi,pi/4):; A:= element(circle(0,1),t):; tangent(A)
Output:

When tangent is called with an element, the tangent will change along with the point on the element.