Derivation of the Derivative
Here's how to use this applet
To reset, click the top-right corner.
The function f can be changed to anything you like! Just type f(x)= ... into the input bar at the bottom.
The point A can be moved by clicking and dragging. Or, in the input bar, you can type in A=(x, f(x)) for whatever value of x you like. But then, it might not drag anymore; reset the construction.
The point B is determined by A and delta-x. Use the red slider to change delta-x. To find a particular value, type delta-x=... into the input bar at the bottom. You can get the delta character by clicking the far-right side of the input bar.
Tim Cieplowski, October 6, 2011, Created with GeoGebra