Casio fx-9860GII - 1.20 Solving a combined quadratic and exponential equation

Using a graphic display calculator
© Oxford University Press 2012: this may be reproduced for class use solely for the purchaser’s institute
Casio fx-9860GII
More complicated functions
1.20 Solving a combined quadratic
and exponential equation
Example 23
Solve the equation x
2
− 2x + 3 = 3.2
− x
+ 4.
Press
MENU
and choose 5: GRAPH and press
EXE
.
The default graph type is Function, so the form Y= is displayed.
Type x
2
− 2x + 3 in Y
1
and press
EXE
.
Then type 3 × 2
− x
+ 4 in Y
2
and press
EXE
.
Press
SHIF T
F3
V-Window and choose
F3
STD to
use the default axes which are −10 ≤ x ≤ 10
and −10 ≤ y ≤ 10.
Press
EXE
and
F6
DRAW.
The calculator displays the curves with the default axes.
Adjust the window to make the quadratic curve fi t the screen better.
Press
F5
G-Solv and
F5
ISCT.
The calculator displays the intersection of the two
straight lines at the point (2.58, 4.50).
The solutions are x = 2.58 and y = 4.50.
To solve the equation,  nd the point
of intersection between the quadratic
function y
1
= x
2
− 2x + 3 and the
exponential function
y
2
= 3 × 2
−x
+ 3.
Note: Type
2
>
(–)
X,i,T
to enter 2
–x
.
The
returns you to
the baseline from the
exponent.
24