The amsmath package provides several matrix environments, each with a different delimiter style: brackets, parentheses, vertical bars or none.
Matrix types
LaTeX
% Crochets (bmatrix)
$\begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix}$ \quad
% Parenthèses (pmatrix)
$\begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$ \quad
% Déterminant (vmatrix)
$\begin{vmatrix} 1 & 2 \\ 3 & 4 \end{vmatrix}$| Environment | Delimiter | Common usage |
|---|---|---|
matrix | Aucun | Matrice nue |
pmatrix | ( ) | Vecteurs, matrices générales |
bmatrix | [ ] | Systèmes linéaires |
vmatrix | | | | Déterminants |
Vmatrix | || || | Normes matricielles |
Large matrices with dots
LaTeX
\[
A = \begin{pmatrix}
a_{11} & a_{12} & \cdots & a_{1n} \\
a_{21} & a_{22} & \cdots & a_{2n} \\
\vdots & \vdots & \ddots & \vdots \\
a_{m1} & a_{m2} & \cdots & a_{mn}
\end{pmatrix}
\]Example: linear system
LaTeX
\[
\begin{bmatrix}
2 & 1 & -1 \\
-3 & -1 & 2 \\
-2 & 1 & 2
\end{bmatrix}
\begin{bmatrix} x \\ y \\ z \end{bmatrix}
=
\begin{bmatrix} 8 \\ -11 \\ -3 \end{bmatrix}
\]