book.tex

%preamble starts here
\documentclass[ ] {book}

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphics}
\usepackage[colorlinks, linkcolor={blue},citecolor={blue},pagecolor={blue},urlcolor={blue},%
 breaklinks, bookmarks, bookmarksopen, bookmarksnumbered]{hyperref}
\hyphenation{Co-or-di-nate Mi-ami Isopy-c-nal}
\makeindex

\newcommand{\degrees}{$^{\circ}$}
\newcommand{\vitem}{\item \vspace{-1.0ex}}
\newcommand{\D}{\displaystyle}
\markboth{}{}

%the next line allows the @character to be used in redefining commands
\makeatletter 
\renewcommand{\section}   {\@startsection{section}   {1}{0pt}{\baselineskip}{0.1pt}{\normalfont\normalsize\bfseries}}
\renewcommand{\subsection}{\@startsection{subsection}{2}{0pt}{-0.5\baselineskip}{0.1pt}{\normalfont\normalsize\bfseries}}
\renewcommand{\paragraph} {\@startsection{paragraph}
{4}{0pt}{-0.5\baselineskip}{-0.5em}{\normalfont\normalsize\bfseries}}
%the next line returns @ to its default usage
\makeatother

\setcounter{tocdepth}{3}
%preamble ends here

\begin{document}
\frontmatter
\include{title}
\mainmatter
\include{chapters}
\backmatter
\include{ref}
\addcontentsline{toc}{chapter}{Index}
\setlength{\textwidth}{12.5cm}
\setlength{\columnsep}{1.0cm}
\printindex
\end{document}