# In Mathjax, how do you get a curly bracket (or brace) to span multiple lines?

How do you write a LaTeX expression that looks like the following

$$f(x)=\begin{cases} 1, & \text{if x<0}.\\ 0, & \text{otherwise}. \end{cases}$$

To do this, you can make use of the cases package.  $$f(x)=\begin{cases} 1, & \text{if x<0}.\\ 0, & \text{otherwise}. \end{cases}$$