Casio fx-9860G SD - Manual (Page 165)

20050401
4-1-2
Simultaneous Linear Equations
○ ○ ○ ○ ○
Example To solve the following simultaneous linear equations for x , y , and z
4 x + y – 2 z = – 1
x + 6 y + 3 z = 1
– 5 x + 4 y + z = – 7
Procedure
1 m EQUA
2 1(SIML)
2(3)
3 e wbw-cw-bw
b wgwdwbw
-fwewbw-hw
4 1(SOLV)
Result Screen
# Internal calculations are performed using a 15-
digit mantissa, but results are displayed using
a 10-digit mantissa and a 2-digit exponent.
# Simultaneous linear equations are solved by
inverting the matrix containing the coefficients
of the equations. For example, the following
shows the solution (
x
1 , x
2 , x
3 ) of a simultane-
ous linear equation with three unknowns.
x
1
a
1
b
1
c
1
–1 d
1
x
2
= a
2
b
2
c
2
d
2
x
3
a
3
b
3
c
3
d
3
Because of this, precision is reduced as the
value of the determinant approaches zero. Also,
simultaneous equations with three or more
unknowns may take a very long time to solve.
# An error occurs if the calculator is unable to find
a solution.
# After calculation is complete, you can press
1 (REPT), change coefficient values, and then
re-calculate.