This sketch shows a function with a tangent line at point A. Point B in the sketch plots out the slope values of the tangent line, so it follows the path of the derivative function.
Using the [b]Move [/b]tool, slide point A along [i]f[/i]([i]x[/i]) to see point B trace out the derivative of [i]f[/i]. You can also look at other functions by double clicking on [i]f[/i]([i]x[/i]) in the algebra pane and entering a different function rule.