# Using LaTeX packages

## Use packages in LaTeX to add more functions. Demonstration of amsmath package and basic math typesetting.

LaTeX offers a lot of functions by default, but in some situations it can become in handy to use so called packages. To import a package in LaTeX, you simply add the \usepackage directive to the preamble of your document:

\documentclass{article}

\usepackage{PACKAGENAME}

\begin{document}
...
\end{document}


## Install a package

When using Linux or Mac, most packages will already be installed by default and it is usually not necessary to install them. In case of Ubuntu installing texlive-full from the package manager would provide all packages available. The MiKTeX bundle in Windows, will download the package if you include it to your document.

## Purpose of packages

There are countless packages, all for different purposes in my tutorials I will explain some of the most useful. To typeset math, LaTeX offers (among others) an environment called equation. Everything inside this environment will be printed in math mode, a special typesetting environment for math. LaTeX also takes care of equation numbers for us:

\documentclass{article}

\begin{document}

$$f(x) = x^2$$

\end{document}

This will result in the following output: $$f(x)=x^2$$ (1)

## Using / Including a package

The automatic numbering is a useful feature, but sometimes it’s necessary to remove them for auxiliary calculations. LaTeX doesn’t allow this by default, now we want to include a package that does:

\documentclass{article}

\usepackage{amsmath}

\begin{document}

\begin{equation*}
f(x) = x^2
\end{equation*}

\end{document}


Now we get the same output as before, only the equation number is removed: $$f(x)=x^2$$

## Summary

• Packages add new functions to LaTeX
• All packages must be included in the preamble
• Packages add features such as support for pictures, links and bibliography

Next Lesson: 04 Math