## (Integral of f(x)dx)

The command gives the approximate value of the definite integral of a function with respect
to the x variable over a specified interval. This command is used in conjunction with the graph
of the function.

While viewing the graph of a function, press
to view the CALCULATE menu.

Press .

If more than one function is graphed, use
to select the desired
curve. A lower limit prompt will appear. Use
to trace the curve to the lower limit and press .
Repeat for the upper limit.

**Note:** If the cursor cannot be placed close enough to the desired limits, use the ZOOM
feature and repeat the process.

Once you have pressed after selecting the upper limit, the region of integration will be
shaded and the value (or approximate value) of the definite integral over the specified interval
will be displayed.

Use ClrDraw in the DRAW menu (press ) to redraw the graph without the shaded region.

**Note:** The command evaluates the integral numerically using a tolerance value of 0.001.