Casio fx-9860GII Instructions Manual page 13

Example 11
Find the maximum point on the graph of y = −x
Press MENU and choose 5: GRAPH and press
The default graph type is Function, so the form Y = is displayed.
Type −x 2 + 3x − 4 and press
SHIF T F3
Press V-Window and choose
which are −10 ≤ x ≤ 10 and −10 ≤ y ≤ 10.
EXE F6
Press and DRAW.
The calculator displays the curve with the default axes.
Adjust the window to make the quadratic curve fi t the screen better.
For help with changing
axes, see your GDC
manual.
Method 1 - using a table
You can look at a table of the values of the function.
MENU
Press and choose 7: TABLE and press
F5
Press SET.
Choose a start and end point for the table and a step of 1.
Use the x-values from the graph you drew.
Press EXIT .
SHIF T
Press SET UP.
Scroll down to Dual Screen and press
© Oxford University Press 2012: this may be reproduced for class use solely for the purchaser's institute
2
+ 3x − 4.
EXE .
EXE .
F3
STD to use the default axes
EXE
.
F1
T+G.
Casio fx-9860GII
If the calculator displays a
EXIT
graph, press to return
to this screen.
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Continued on next page
Using a graphic display calculator 13