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 MATH 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.

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 to redraw the graph without the shaded region.

**Note:**The accuracy goal of the calculator's algorithm is 6 significant digits.
A warning ("Questionable accuracy") is displayed when it appears that the goal has
not been obtained.