Chapter 13 – Troubleshooting

Error testing

\documentclass{article}
\begin{document}
% wrong:
%\Latex\ says: Hello world!
% correct:
\LaTeX\ says: Hello world!
\end{document}

Warning

\documentclass{article}
\renewcommand{\familydefault}{\sfdefault}
\begin{document}
\emph{Hello world!}
\end{document}