HP 40G manual Cursor. You need to have at least, Two selected expressions, Symbolic view. Displays

Function	Description (Continued)
Signed area	Select Signed area to find the
	numeric integral. (If there are two or
	more expressions checkmarked,
	then you will be asked to choose the
	second expression from a list that
	includes the x-axis.) Select a starting
	point, then move the cursor to
	selection ending point. The result is
	saved in a variable named AREA.
Intersection	Select Intersection to find the
	intersection of two graphs nearest
	the cursor. (You need to have at least
	two selected expressions in
	Symbolic view.) Displays the
	coordinate values and moves the
	cursor to the intersection. (Uses
	Solve function.) The resulting x-
	value is saved in a variable named
	ISECT.

Shading area You can shade a selected area between functions. This process also gives you an approximate measurement of the area shaded.

1.Open the Function aplet. The Function aplet opens in the Symbolic view.

2.Select the expressions whose curves you want to study.

3.Press￿>3/27@ to plot the functions.

4.Press *>, or *A, to position the cursor at the starting point of the area you want to shade.

5.Press 0(18a.

6.Press )&1a, then select Signed area and press 2.a.

7.Press 2., choose the function that will act as the boundary of he shaded area, and press 2.a.

8.Press the *>, or *A,￿key to shade in the area.

9.Press 2.ato calculate the area. The area measurement is displayed near the bottom of the screen.

To remove the shading, press >3/27@ to re-draw the plot.

3-10 Function aplet