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}

Order of a matrix

• 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.

Matrix notation

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.