beginbmatrix

The bmatrix environment is a LaTeX tool for typesetting matrices with square brackets, provided by the amsmath package. It is commonly used in mathematical documents to clearly denote matrix structures without additional notation.

To use it, place the environment in math mode and enclose your matrix between \begin{bmatrix} and \end{bmatrix}. Inside, separate columns with & and terminate rows with \\. For example, a 2x2 identity matrix can be written as a matrix with 1 and 0 entries in the appropriate positions. This produces a visually standard square-bracketed matrix.

You can use the bmatrix environment inline within a mathematical expression or in displayed equations. For inline use, wrap the environment in dollar signs, as in $ \begin{bmatrix} a & b \\ c & d \end{bmatrix} $. For displayed equations, you can place it within a displayed math environment such as \[ ... \] or equation environments.

The bmatrix environment is one of several delimiter-based matrix environments in amsmath. Others include pmatrix (parentheses), Bmatrix (braces), vmatrix (vertical bars), and Vmatrix (double vertical bars). If square-bracketed notation is not desired, choosing an alternative environment provides the appropriate delimiters without changing the matrix entries.

Note that using bmatrix requires including \usepackage{amsmath} in the document preamble. The environment itself automatically scales to fit the matrix content, maintaining proper spacing and alignment.