# Dipa/Help

From Maths

## 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 [math](\frac{a+b}{\sqrt{c} })[/math]
- 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 [math]\left(\frac{a+b}{\sqrt{c} }\right)[/math] - notice the bigger brackets

- Suppose you just want a left thing but no right thing. A . means "nothing". So for example:
- [math]\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. [/math] - 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: [math](\big(\Big(\Bigg([/math]

## A matrix

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

- [math]\left(\begin{array}{ccc} a & b & c \\ d & e & f \\ h & i & j\end{array}\right)[/math] This is just \left( then an array then a \right)