Texas Instruments TI-82 Manual page 24

Thus z = 2, so y = –1 and x = 1.
2.6.4 Determinants and Inverses: Enter this 3×3 square matrix as [A]:
−
 
1 2 3
 
− 
1 3 0 , press MATRX ► 1 MATRX 1 ENTER. You should find that

 
−
2 5 5
 
Since the determinant of matrix [A] is not zero, it has an inverse, [A]
inverse of matrix [A], also shown in Figure 2.68.
Now let's solve a system of linear equations by matrix inversion. Once more, consider
The coefficient matrix for this system is the matrix
[ ]
Figure 2.68: A and [A]
If necessary, enter it again as [A] in your TI-82. Enter the matrix
2 ENTER to calculate the solution matrix (Figure 2.69). The solutions are still x = 1, y = –1, and z = 2.
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G T
RAPHING ECHNOLOGY
Figure 2.67: Final matrix after row operations

1

− 
1

2

–1
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G : TI-82
UIDE
−
 1 2 3 
 
− 
1 3 0 . To calculate its determinant,

 
−
2 5 5
 
[ ]
A = 2, as shown in Figure 2.68.
–1
. Press MATRX 1 x
−

2 3

3 0 that was entered in the previous example.


−
5 5

Figure 2.69: Solution matrix
 9 
 
−  
as [B]. Then press MATRX 1 x
4
 
17
 
-1
ENTER to calculate the
− + =

x 2 y 3 z 9

− + = −
x 3 y 4


− + =
2 x 5 y 5 z 17

-1
× MATRX