Texas Instruments TI-82 Keystroke Manual page 58

and two columns has been entered as matrix A.) Highlight the EDIT menu at the top of the screen,
and press 2 for matrix B. In our system of equations matrix B has two rows and one column, so
type a 2 as the row dimension and press ENTER. Then type a 1 as the column dimension and press
ENTER (or just press ENTER if the column dimension is already 1), so that the display appears as
on the left below. Enter the numbers into the matrix as before until the display appears as on the
right below.
Now that the matrices have been entered, press 2nd [QUIT] to return to the Home screen. If you
would like to see matrix A displayed on the Home screen, press MATRX, and with the NAMES
menu highlighted at the top of the screen, press ENTER or 1. The character [A] will be displayed
on the Home screen. Press ENTER to have the calculator display matrix A as shown on the left
below. Press MATRX 2 to display the character [B] on the Home screen. Press ENTER to see
matrix B as shown on the right below. Although you don't really have to display these matrices
before solving the system of equations, it isn't a bad idea to look at them on the Home screen just
to be sure that you have entered the numbers correctly. If you notice a mistake, you can still go
back and make corrections at the matrix editing screen. After selecting the matrix you want, use
the arrow keys to go to the part that needs to be corrected and type and enter the corrections.
To solve the system we need to find the matrix product
of matrix A. (You don't have to worry about what that inverse is.) On the Home screen this
matrix product will appear as [A]
to produce the [A]. Then press the
instead.) Finally, press MATRX 2 to produce the [B]. With the screen displaying [A]
press ENTER to display a
the values for x and y, respectively, which form the solution of the system of equations. Thus, the
solution of the system is
[B]. To produce this expression on screen, press MATRX 1
-1
−
1
x key to produce the exponent
2 × matrix as on the top of the next page showing, from top to bottom,
1
( − = y
, 1 ) 1 ; that is, x , 1
−
1
A B , where
− . (Do not use ^-1
1
= −
1 .
TI-83 53
−
1
A denotes the inverse
-1
[B],