Matrices and Arrays

Writing a matrix in LaTeX requires the amsmath package, which is the gold standard for math typesetting. (Don't worry, in LetX and most modern templates, this package is already included).

The Matrix Environments

LaTeX provides several matrix environments. The only difference between them is the type of bracket (or lack thereof) surrounding the matrix.

• matrix: No brackets
• pmatrix: Parentheses ()
• bmatrix: Square brackets []
• Bmatrix: Curly braces {}
• vmatrix: Vertical lines || (useful for determinants)
• Vmatrix: Double vertical lines || ||

Building a Matrix

Inside a matrix environment, you build the grid row by row.

• Use an ampersand & to separate columns.
• Use a double backslash \\ to end a row and start a new one.

\[
M = \begin{bmatrix}
    1 & 2 & 3 \\
    4 & 5 & 6 \\
    7 & 8 & 9
\end{bmatrix}
\]

You can make them as large as you want, and the brackets will automatically scale to fit the contents perfectly!

Vectors

A vector is just a matrix with a single column.

\[
\vec{v} = \begin{pmatrix}
    x_1 \\
    y_1 \\
    z_1
\end{pmatrix}
\]

Example of a theoretical matrix:

\[
A = \begin{bmatrix}
    a_{11} & a_{12} & \dots  & a_{1n} \\
    a_{21} & a_{22} & \dots  & a_{2n} \\
    \vdots & \vdots & \ddots & \vdots \\
    a_{m1} & a_{m2} & \dots  & a_{mn}
\end{bmatrix}
\]

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