# Brackets[..] symbol in LaTeX

Symbol/Unicode Brackets/U+005B,U+005D
Type of symbol Calculate expression inside first
Package (requirement) No
Argument No
Latex command \left[arg\right]
Example \left[arg\right] → [arg]

You can use the bracket key [, ] on the keyboard to type the bracket symbol in latex. But if you use fractions in the equation, the size of the bracket will not be adjusted automatically. Below are some examples.

\documentclass{article}
\begin{document}
$$[a+b]$$
$$[x^2 + y^2]$$
$$[\frac{1}{a_1} + \frac{1}{a_2}]$$
\end{document}

Output :

If you use fractions or large size equations, the best method would be to write \left[arg\right] command. This will automatically adjust the size of the bracket based on the size of your equation.

\documentclass{article}
\begin{document}
$$\left[x^2 + y^2\right]$$
$$\left[\frac{1}{a_1} + \frac{1}{a_2}\right]$$
$$\left[\frac{\frac{1}{x}}{\sin x}\right]$$
\end{document}

Output :