# large braces for specifying values of variables by condition

How do I typeset something like, X = 0 if a=1, 1 otherwise, using those huge left braces and specifying each condition in a line?

-

The »cases« environment from amsmath does the trick.

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$$X= \begin{cases} 0, & \text{if}\ a=1 \\ 1, & \text{otherwise} \end{cases}$$
\end{document}

-
x = \begin{cases}
0, & \text{if } a = 1, \\
1, & \text{otherwise}.
\end{cases}


amsmath is needed for \text.

-