Matrix Operations on the TI-89

Entering a Matrix: Press [APPS] and select [Data/Matrix Editor]. Select either 1:Current, 2:Open..., or 3, New where appropriate.
Selecting New and entering the information about the matrix as follows:

Press [HOME] to return to the Home screen. Now pressing a and [ENTER] will show you the matrix.

Row Operations : The Row operations can be found by pressing [2nd][MATH] selecting [4: Matrix] and selecting [J: Row ops]. Row
ops is far enough down the list that moving up the list is faster. Here are examples of row operations :

Note: If you are doing many row operations on the same matrix you should use [ANS] instead of the name of the matrix after the first
row operation .

Row Echelon Form (ref) and Reduced Row Echelon Form
Press [2nd][MATH] select [4:Matrix]. Select the
desired form followed by the name of the matrix and press
enter. For example:

Inverse Matrices: Select the name of the matrix and raise it
to the –1 power . The matrix A above is not invertible so we

If you want your results in fractions select [Exact/Approx] after pressing [MODE]. Set the calculator to [2: EXACT] then all
computations will come out in fractions .

Addition and Multiplication : These operations are done with the regular multiplication and addition keys along with the names of
the matrices. For example consider the matrices B and C shown on the left with the computations shown on the right.

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