\begin{math}
f_A(x) = 
\begin{cases}
	1,  \mbox{if }x \in A \\
	0,  \mbox{if }x \notin A 
\end{cases}
\end{math}

This is a mathematical expression  
$$
	 \sum_{k=0}^{n-1}x^k =\frac{x^n-1}{x-1}
$$

and this is a lot of math symbols 
$ \alpha \beta \gamma \delta \leq \infty \times \Theta $

This is another expression
$$
	\sum_{k=0}^\infty\frac{(-1)^k}{k+1} = \int_0^1\frac{dx}{1+x}
$$

This is an array
$$
      \left(
      \begin{array}{rcl}
      i_{11}&i_{12}&i_{13}\\
      i_{21}&i_{22}&i_{23}\\
      i_{31}&i_{32}&i_{33}\\
      \end{array}
      \right)
$$

This is a table
\begin{table}[t]
\caption{Member of a fuzzy set}
\begin{center}
\begin{tabular}{|c|c|c|}
\hline
Height (cm)&\multicolumn{2}{|c|}{Degree of membership} \\ % see next table for explanation of this command
\cline{2-3}
&Degree1&Degree2 \\
\hline
150&0&0.00\\
157&0&0.00\\
170&0&0.00\\
171&0&0.05\\
\hline
\end{tabular}
\end{center}
\label{t_fuzzyset}
\end{table}

This is the citation of reference in the text.  The textbook by Comer (\cite{Come95}) 
is a popular reference on Network architecture.
 
Now the bibliography

\begin{thebibliography}{} 
\bibitem[Come95]{Come95} Comer,
D. E., {\it Internetworking with TCP/IP:
Principles, Protocols and Architecture},
volume 1, 3rd edition. Prentice-Hall,
1995.
\end{thebibliography}

Now the bibliography

\begin{thebibliography}{} 
\bibitem[Come95]{Come95} Comer,
D. E., {\it Internetworking with TCP/IP:
Principles, Protocols and Architecture},
volume 1, 3rd edition. Prentice-Hall,
1995.
\end{thebibliography}

\begin{thebibliography}{} 
\usepackage{chicago} 
\bibliography{prabhasbib}
\bibliographystyle{chicago}

\end{thebibliography}

End of example.