LaTeX is a typesetting markup language that produces beautiful PDF documents with little to no layout effort required for a great result. You don't have to be a professional typist to make great looking reports, charts, or other documents. And rendering math has never been easier!

This:

\( \int_a^b f(x) \, \mathrm{d}x \)

Gets you this:

$\int_a^b f(x) \, \mathrm{d}x$

Which is goregous. No more editing equations with Word or LibreOffice, no trying to figure out what to click to get the formatting correct. Just write the equation with simple symbols, and LaTeX does the rest.

Simple document example

Here is an example LaTeX document:

\documentclass{article}
\begin{document}
\section{This is the First Section}
\label{section:first}
This is the first section! It is before the second section\footnote{Generally, at any rate}.

\section{This is the Second Section}
This is a reference to Section \ref{section:first}, which is automatically numbered.
\end{document}

It produces this pdf:

This example does a few things:

• Declares the document class to be article
• Starts sections with the \section{} tag
• Labels sections for cross-referencing (\label{})
• References a label (\ref{})
• Uses a footnote (\footnote{})

Here is a simple tutorial in $\LaTeX$.