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. Enter the value of the lower limit at the prompt, or trace the curve to the approximate point. 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.