F f f 2 2, A j 1, T a j 1 – Casio fx-570MS User Manual
Page 40: A j 3, A = 4
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Explanation
Explanation
Example 2
Example 2
Use a matrix to solve the simultaneous equations
2
x
– 3
y
= 18
3
x
+ 2
y
= 1
{
}
.
Placing simultaneous equations
ax
+
by
=
k
cx
+
dy
=
l
{
}
inside matrices A =
a b
c d
, X =
x
y
, and B =
k
l
makes it possible to express them as AX = B.
This means that if inverse matrix A
-1
exists for Matrix A, then X = A
-1
B.
1
.
Select the MAT Mode.
F F F 2
2
.
Input
2 –3
3 2
for Matrix A and
18
1
for Matrix B.
A j 1
(Dim)
1
(A)
2
=
2
=
2
=
D
3
=
3
=
2
= t
A j 1
(Dim)
2
(B)
2
=
1
=
18
=
1
= t
3
.
Determine in inverse for Matrix A.
A j 3
(Mat)
1
(A)
a =
4
.
Multiply the inverse matrix by Matrix B (from the left).
-
A j 3
(Mat)
2
(B)
=
The above procedure tells us that
x
= 3 and
y
= –4.
Operation
Matrix Problems
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