Operation Manual

Chapter 10: Matrices 148
Defining a Matrix
What Is a Matrix?
A matrix is a two-dimensional array. You can display, define, or edit a matrix in the matrix editor. You
can also define a matrix using the MTRX shortcut menu (t `).The TI-84 Plus C has 10 matrix
variables,
[A] through [J]. You can define a matrix directly in an expression. A matrix, depending on
available memory, may have up to 99 rows or columns. You can store only real numbers in TI-84 Plus
matrices. Fractions are stored as real numbers and can be used in matrices.
Selecting a Matrix
Before you can define or display a matrix in the editor, you first must select the matrix name. To do so,
follow these steps.
1. Press y| to display the
MATRX EDIT menu. The dimensions of any previously defined
matrices are displayed.
2. Select the matrix you want to define. The MATRX EDIT screen is displayed.
Accepting or Changing Matrix Dimensions
The dimensions of the matrix (row × column) are displayed on the top line. The dimensions of a new
matrix are
1×1. You must accept or change the dimensions each time you edit a matrix. When you
select a matrix to define, the cursor highlights the row dimension.
• To accept the row dimension, press Í.
• To change the row dimension, enter the number of rows (up to 99), and then press Í.
The cursor moves to the column dimension, which you must accept or change the same way you
accepted or changed the row dimension. When you press Í, the rectangular cursor moves to the
first matrix element.
Viewing and Editing Matrix Elements
Displaying Matrix Elements
After you have set the dimensions of the matrix, you can view the matrix and enter values for the
matrix elements. In a new matrix, all values are zero.