How to get started to typeset mathematical proofs with LaTeX?

Question

I want to start using LaTeX to organize my proofs into a readable fashion. This motif is due to my professors preferring e-mail communication instead of reading a chicken-scratch proof. I know enough LaTeX such that I can post on math.SE and make my question readable, but I do not know how to include LaTeX in a document.

How do I make my proof into a LaTeX document?

Answer 1

The skeleton is as follows,

\documentclass[preview,border=12pt,varwidth]{standalone}
%\documentclass{article}
\usepackage{mathtools}
\usepackage{amsthm}
\title{My Title}
\author{My Name}
\date{\today}

\newtheorem{thm}{Theorem}
\begin{document}
\maketitle

\begin{thm}
$ax^2+bx+c=0$ has 2 real roots if $D>0$.
\end{thm}

\begin{proof}
This is my proof that $ax^2+bx+c=0$ has 2 real roots if $D>0$.
\[
x_{1,2}=\frac{-b\pm\sqrt{D}}{4ac}
\]
\end{proof}
\end{document}

For more detailed at a glance tutorial, visit Theorem.