Tangents Tool
Activate the tool, then:

Select a point on a conic (or a function) to create all the tangents to the conic (or function) at the selected point.

Select a point not belonging to a conic to create all the tangents to the conic passing through the selected point.

Select a point not belonging to a function to create the tangent line to the function at its point with the same xcoordinate as the selected one. For example, given f(x) and a point A not on it, the tool creates the tangent line to f(x) at (x(A), f(x(A)).

Select a line and a conic to create the tangent lines to the conic that are parallel to the selected line.

Select two circles to create their common tangent lines (up to 4).
