# Delimiters and cases

Use `\left` and `\right` when delimiters should grow with their contents.

```latex
\left(\frac{x+1}{x-1}\right)^2
```

```latex
\left\langle u,v\right\rangle = \sum_{i=1}^{n}u_i v_i
```

```latex
|x| = \begin{cases}
x, & x \geq 0,\\
-x, & x < 0.
\end{cases}
```

```latex
f(x)=\begin{cases}
x^2, & |x|\leq 1,\\
2|x|-1, & |x|>1.
\end{cases}
```