# Dipa/Help

## Overview

This is a quick reference for how to do things that are not symbols, like matrices and stuff

## Left & Right

• Example <mm>(\frac{a+b}{\sqrt{c} })</mm> - looks like $(\frac{a+b}{\sqrt{c} })$
• We use \left( and \right) to get the things after the left and right big enough to fit through the middle, in this case:
• <mm>\left(\frac{a+b}{\sqrt{c} }\right)</mm> gives $\left(\frac{a+b}{\sqrt{c} }\right)$ - notice the bigger brackets
• Suppose you just want a left thing but no right thing. A . means "nothing". So for example:
• $\left\{\begin{array}{lr} f(2t) & \text{if }t\in[0,\frac{1}{2}] \\ g(2t) & \text{if }t\in[\frac{1}{2},1]\end{array}\right.$ - here we have a \left\{ and \right. around the array. So it sizes to match.

### Manual sizing

• \big, \Big, \Bigg make things bigger, for example:
• (\big(\Big(\Bigg( looks like: $(\big(\Big(\Bigg($

## A matrix

This is just \left( and \right) around an array, like:

• $\left(\begin{array}{ccc} a & b & c \\ d & e & f \\ h & i & j\end{array}\right)$ This is just \left( then an array then a \right)