Tool Palettes Curves > Lines (Tangent) > Line tangent from/to curve > To draw a tangent line between two curves

Curves > Lines (Tangent) > Line tangent from/to curve

Allows you to draw a keypoint line tangent to two curves.

To draw a tangent line between two curves

Click the Curves > Lines (Tangent) > Line tangent from/to curve icon, or choose Lines (Tangent) > Line tangent from/to curve from the Curves palette menu.
Click the first curve the tangent line will touch.
Click the second curve the tangent line will touch.

The Line tangent from/to curve tool calculates the line tangent to both curves.

If it cannot find a tangent, it prints a message in the prompt line.
If it finds more than one tangent, it uses the tangent closest to where you clicked.