As shown in the EPIC screen below, there are several features available within the Secant Line option. In addition to specifying the two points on a curve for the secant line, you may specify that a number of secant lines be drawn. If more than one line is to be drawn (say 10 lines are requested), then they are drawn according to the following guidelines:

• the first point is held fixed;
• the difference between the points is divided into 10 equal parts;
• 10 secant lines are drawn, one for each of the 10 parts.
  

For example, if 10 lines are requested, and the first and second points are 2 and 3 respectively, then secant lines will be drawn using the points

This process very nicely illustrates the concept of secant lines approaching the tangent line. At your discretion, the drawing will pause after each line, with the coordinates used for the last line, the point separation (h), and the slope of the last line shown at the top of the screen. At anytime during "pause" mode, you can remove pause.

Finally, the selection of the first and second points can be made by entering values (e.g., 2.5), expressions (e.g., sqrt 2), or by pointing and clicking the mouse on the graph.