HP 38g Graphing Calculator - Manual (Page 84)

To move the
cursor
To clear
shading
To change the starting position of the cursor after having
selected an operation, press {{MENU}}, move the cursor, and
re-select the FCN operation.
To remove the shading produced by the AREA operation,
press I PLOT I to re-draw the plot.
FCN Operations
Root Select Root to find the root x-value nearest the crosshairs. If
no root is found, but only an extremum, then the result is
labeled EXTR : instead of root :. (The root-finder is also
used in the Solve aplet. See also “Interpreting Results,” in
chapter 4.) The resulting x-value is saved in a variable named
Root.
Extremum Select Extremum to find the maximum or minimum nearest
the crosshairs. This displays the coordinate values and moves
the crosshairs to the extremum. (This uses the derivative.)
The resulting value is saved in a variable named Extremum.
Slope Select slope to find the numeric derivative at the point
nearest the crosshairs. The result is saved in a variable named
Slope.
Area Select 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 shade a
region between the curve and the x-axis (or another curve),
and between the starting point and the current position. The
shaded region will be between the two curves. The Area is
the signed value of the shaded area. Areas below the x-axis
are negative. The result is saved in a variable named Area.
Intersection Select intersection to find the intersection of two graphs
nearest the crosshairs. (You need to have at least two selected
expressions in Symbolic view.) Displays the coordinate values
and moves the crosshairs to the intersection. (Uses Solve
function.) The resulting x-value is saved in a variable named
Isect.
3-20 Plotting and Exploring Functions