\section{PI Constant Pi}

\subsection{Usage}

Returns a \verb|double| (64-bit floating point number) value that represents pi (ratio between the circumference and diameter of a circle...).  Typical usage 
\begin{verbatim}
   y = pi
\end{verbatim}
This value is approximately 3.141592653589793.
\subsection{Example}

The following example demonstrates the use of the \verb|pi| function.
\begin{verbatim}
--> pi

ans = 

    3.1416 

--> cos(pi)

ans = 

 -1 


\end{verbatim}
