## SecantTangent Applet

This applet draws a tangent line to a graph at a point marked by a red draggable disk. By dragging this disk, you can move the point. A secant line is drawn from this point to another point, which is marked by a green draggable disk. You can also set the x-coordinates of the point by entering them in the input boxes at the bottom of the applet. The slope of the secant line is shown at the upper left.

You can change the viewing rectangle in several ways:

- Clicking on the graph will zoom in on the point where you click.
- Clicking on the graph while holding down the shift key will zoom out at the point where you click.
- Dragging the mouse from one point to another on the graph will create a rectangle on the screen. When you release the mouse button, that portion of the graph will be enlarged to fill the viewing rectangle.
This applet is one of the configurable applets provided by David Eck, author of Java Components for Mathematics.