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Fcn operations – HP 38g Graphing Calculator User Manual

Page 84

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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