LaTeX matrix (square or curly brackets)

\[
\begin{matrix}
a & b \\
c & d
\end{matrix}
\]

\[ \begin{matrix} a & b \\ c & d \end{matrix} \]

All rows are separated by double backslashes \\ and items in each row are separated by &. The matrix doesn't draw any brackets.

pmatrix

\[
\begin{pmatrix}
a & b \\
c & d
\end{pmatrix}
\]

\[ \begin{pmatrix} a & b \\ c & d \end{pmatrix} \]

The pmatrix generates the common type of matrices with curly brackets.

bmatrix

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

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

The bmatrix generates a matrix as pmatrix but it's more suitable in case that the matrix has three or more rows or columns.

\[
\begin{bmatrix}
a_{11} & \cdots & a_{1n} \\
a_{21} & \cdots & a_{2n}
\end{bmatrix}
\]

\[ \begin{bmatrix} a_{11} & \cdots & a_{1n} \\ a_{21} & \cdots & a_{2n} \end{bmatrix} \]

vmatrix

\[
\begin{vmatrix}
a & b \\
c & d
\end{vmatrix}
\]

\[ \begin{vmatrix} a & b \\ c & d \end{vmatrix} \]

The vmatrix is better than other commands if you want to draw the determinant of a matrix.

Vmatrix

\[
\begin{Vmatrix}
a & b \\
c & d
\end{Vmatrix}
\]

\[ \begin{Vmatrix} a & b \\ c & d \end{Vmatrix} \]

array

\[
\begin{array}{cc}
a & b \\
c & d
\end{array}
\]

\[ \begin{array}{cc} a & b \\ c & d \end{array} \]