\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{ctex}
\usepackage{amsmath} %% This is package for typesetting derivations.
\title{test for \LaTeX\ document}
\author{thwzjx}
\date{\today}
\begin{document}
\maketitle
\tableofcontents
\section{chap1}
\subsection{Introduction for Real Analysis}
\end{document}