## Friday, May 20, 2011

### Secant & Tangent

The graph below shows the process of getting instantaneous rate of change (slope of tangent) from average rate of change (slope of secant).

The red curve is given as y = g(x). Take note that the average rate of change of y from point A to point B is
$m=\frac{y_2-y_1}{x_2-x_1}$.

Drag point B to observe the change of the slope of secant (m is used to represent slope). As point B is getting nearer to point A, the value of the slope of secant is approaching to the value of the slope of tangent at point A.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)

Betty, Created with GeoGebra