Matrices

Definition

• A matrix is a rectangular group of numbers (or symbols) with a given number of rows and columns.

Example

• The following matrix has two rows and three columns, and is described as a "two by three" (2x3) matrix.

LaTeX

\begin{bmatrix}
    3 & 6 & 2  \\
    5 & 1 & 10
\end{bmatrix}

Notation

• There are a few different ways to represent a matrix. The easiest is with an bold uppercase letter: A

code (Python)

A = [[3, 6, 2], [5, 1, 10]]

print(A)

Notes

• The plural of matrix is matrices.
• The size of a matrix is called its dimension or order. It is written with as rows x columns. A matrix with 2 rows and 3 columns is written as 2x3.
• Two matrices are considered equal if and only if:
  • They have the same number of rows.
  • They have the same number of columns.
  • Each corresponding element is equal. i.e. x1₁₁ = x2₁₁
• The 'numpy.matrix' is depreciated, in favour of regular arrays.