Texas Instruments TI-82 Getting Started page 26

Figure I.75: Matrix
Add the two matrices say
1 MATRX 2 ENTER. Subtraction is performed in a similar manner. Now set the dimensions of matrix
C
to 2 3 and enter the matrix:
MATRX 3 MATRX 1 ENTER. If you tried to multiply
because the dimensions of the two matrices do not permit multiplication in this way.
I.6.3 Row Operations: Here are the keystrokes necessary to perform elementary row operations on a matrix.
Your textbook provides more careful explanation of the elementary row operations and their uses.
To interchange the second and third rows of the matrix
MATRX 8 [rowSwap ( ] MATRX 1 , 2 , 3 ) ENTER (see Figure I.77). The format of this command is
rowSwap(matrix, row1, row 2).
To add row 2 and row 3 and store the results in row 3, press MATRX
ENTER. The format of this command is row+(matrix, row1, row2).
To multiply row 2 by
MATRX 0 [*row( ] (-) 4 , MATRX 1 , 2 ) ENTER. The format of this command *row(scalar,
matrix, row ).
Figure I.77: Interchange rows 2 and 3
To multiply row 2 by
MATRX ALPHA A [*row + (] (-) 4 , MATRX 1 , 2 , 3 ) ENTER (see Figure I.78). The format of this
command is *row+(scalar, matrix, row1, row2).
Technology Tip: Note that your TI-82 does not store a matrix obtained as the result of any row operations.
So when you need to perform several row operations in succession, it is a good idea to store the result of
each one in a temporary place. You may wish to use matrix
For example, use elementary row operations to solve this system of linear equations:
I-26
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A
A and B , create B
2 0
1 5
4 and store the results in row 2, thereby replacing row 2 with new values, press
4 and add the results to row 3, thereby replacing row 3 with new values, press
Figure I.76: Matrix
(with the same dimensions as
3
C .
as For matrix multiplication of
1
A C ,
by
A that was defined in Figure I.75, press
Figure I.78: Add
E
to hold such intermediate results.
B
A ) and then press MATRX
C
by
your TI-82 would signal an error
9 [row + ( ] MATRX 1 , 2 , 3 )
4 times row 2 to row 3
x 2y 3z
x 3y
2x 5y 5z
TI-82 Graphics Calculator
A ,
press
9
4 .
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