IV. Special Graphs

A. Derivative

In calculus it can be very useful to see the graph of a derivative. The TI-89 will draw the graph of the derivative of a function. You will need to use the nDeriv function which is found in the MATH/Calculus menu.

You can use the graph of the derivative to determine where the function is increasing (derivative is positive) and where the function is decreasing (derivative is negative), and where the function has a maximum or minimum (where the derivative is zero or undefined). The graph of the derivative may take a few moments to draw. This is because the calculator is using numerical approximation to determine the derivative values. Once the derivative is drawn, you can use Trace, TABLE, etc, on the graph.

Press to access
the Y=Editor. Enter
the function and the
derivative.
Use TABLE to help
find a window. Press
and enter
some values for x.

Set a WINDOW.
Press .

From the Y=Editor screen
press to
access the STYLE menu.
Select 4:Thick for the
derivative graph.
Press to
draw the graphs.

 

Derivatives
Greatest Integer
Integral
Inverse
Piecewise
I. Entering
Graphs
II. Windows
& Styles
III. Working
with Graphs
IV. Special
Graphs
V. Other
Graph Modes