Using any text editor you can make a file like the one shown in the yellow box below. Such raw' text is referred to as LaTeX source''. Using the LaTeX program, it is converted to a beautifully formatted document; the compiled version of the sample source is shown further below in the white box.
 \documentclass[12pt]{article} \newcommand{\piRsquare}{\pi r^2} % This is my own macro !!! \title{My Sample \LaTeX{} Document} % used by \maketitle \author{\L\"{a}rs Schl{\oe}ff\d{o}ng\"{e}n, } % used by \maketitle \date{July 14, 2005} % used by \maketitle \begin{document} \maketitle % automatic title! I typed this file with a plain text editor. (I used \textbf{pico} and \textbf{emacs}.) End of paragraph. This is my second paragraph. The area of a circle is $\pi r^2$; again, that is $\piRsquare$. My score on the last exam\footnote{May 23} was $95 \pm 5$. \section{Formulae; inline vs. displayed} I insert an inline formula by surrounding it with a pair of single \$symbols; what is$x = 3 \times 5$? For a \emph{displayed} formula, use double-\$ before and after --- include no blank lines! $$\mu^{\alpha+3} + (\alpha^{\beta}+\theta_{\gamma}+\delta+\zeta)$$ \subsection{Numbered formulae} Use the \emph{equation} environment to get numbered formulae, e.g., $$y_{i+1} = x_{i}^{2n} - \sqrt{5}x_{i-1}^{n} + \sqrt{x_{i-2}^7} -1$$ $$\frac{\partial u}{\partial t} + \nabla^{4}u + \nabla^{2}u + \frac12 |\nabla u|^{2}~ =~ c^2$$ \section{Acknowledgments} Thanks to my buddies {\AE}schyulus and Chlo\"{e}, who helped me define the macro \verb9\piRsquare9 which is $\piRsquare$. The end. \end{document} % End of document. `