Matrix definition

A matrix is a rectangular array of numbers, symbols, or expressions, arranged in rows and columns.
Basically, it’s a 2D grid of values.

Examples of matrices

3x3 matrix of numbers:

\begin{bmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{bmatrix}

2x2 matrix of variables:

\begin{bmatrix} a & b \\ c & d \end{bmatrix}

The order is the number of rows and columns in a matrix.
It is written as m x n, where:
- m = number of rows
- n = number of columns
For example, a matrix with 3 rows and 4 columns has an order of 3 x 4.

A matrix is a table of values written in square brackets or parentheses - [] or ().

We usually represent a variable that holds a matrix with a capital [and bold] letter, e.g. A, B, or M.

Question	Answer
What is a matrix?	A rectangular array of numbers, symbols, or expressions, arranged in rows and columns; basically a 2D grid of values.
What is the order of a matrix?	The number of rows and columns, written as m \times n, where m = number of rows and n = number of columns.
How is matrix order typically written?	As m \times n, e.g. a matrix with 3 rows and 4 columns has order 3 \times 4.
How are matrix values typically enclosed?	In square brackets `[]` or parentheses `()`.
How do we denote a variable that holds a matrix?	With a capital (and often bold) letter, e.g. A, B, or M.
Give an example of a 3 \times 3 matrix of numbers.	\begin{bmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{bmatrix}
Give an example of a 2 \times 2 matrix of variables.	\begin{bmatrix} a & b \\ c & d \end{bmatrix}