How to write conditional equations with one-sided curly brackets [duplicate]

I want to write a conditional expression such as the following.

What is the best way to express such conditional expressions in Latex?

-

marked as duplicate by Werner, Papiro, Martin Schröder, Heiko Oberdiek, Paul GaboritJun 18 at 6:07

use cases or dcases. – Peter Grill Mar 7 '12 at 20:05

I think this is a job for cases from the amsmath package

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$f(x)= \begin{cases} \frac{x^2-x}{x},& \text{if } x\geq 1\\ 0, & \text{otherwise} \end{cases}$
\end{document}


or if you would prefer a displaystyle fraction, then you could use dcases from the mathtools package, which extends (and loads) the amsmath package.

\documentclass{article}
\usepackage{mathtools}

\begin{document}
$f(x)= \begin{dcases} \frac{x^2-x}{x},& \text{if } x\geq 1\\ 0, & \text{otherwise} \end{dcases}$
\end{document}

-

Just for the sake of completeness: There is a pseudo-parenthesis . that can be used to terminate an opening parenthesis:

\documentclass{standalone}

\begin{document}
$\left\{a+b=c\right.$
\end{document}


Output:

-
You should expand this answer to show how to use this to produce the output in the original image. – Peter Grill Mar 10 '12 at 1:04
@PeterGrill: Well, there are ways, but cases and dcases are much much more suitable for this task. Are there conditions where these environments are not available? – krlmlr Mar 10 '12 at 5:48
I actually like your answer better. – 0rkan Sep 25 at 3:09