Casio fx-9860GII - Page 7

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
Example 6
Solve the equations 2x + 4y + 2z = 8
x + 2y + z = 4
3x − y + z = −9
Press
MENU
. You will see the dialog box as shown on the right.
Choose A: EQUA and press
EXE
.
From the menu, choose Simultaneous and press
F1
.
Choose equations in three unknowns and press
F2
.
You will see the template on the right.
Type the coeffi cients from the three equations into the template,
pressing
EXE
after each number.
Press
F1
and the calculator will solve the equations,
giving the solutions as X, Y and Z.
The GDC solves the equations by an inverse matrix method.
In this example there is an error because the matrix is singular,
which means that there will be no unique solution.
To fi nd the solution you can use the reduced row echelon form
method instead.
Press
MENU
1
Press
OPTN
|
F2
MAT |
F6
|
F5
Rref
Press
EXIT
EXIT
|
F4
MATH |
F1
MAT |
F3
m × n
Choose m as 3 and n as 4 and press
EXE
.
If there are previous
equations in the memory,
press
EXIT
until you return
to this menu.
The equations must be in
the correct order.
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