\label{Authoring_Dynamic_Plot_Curve_Function}

The \textbf{function} tag allows you to specify the curve to be 
plotted as a formula, instead of numerical data.

The function must be a mathematical expression.
Use the independent variable ``x'' for cartesian plots and ``t'' for polar 
plots.
Implicit multiplication is not accepted by Gnuplot.
The following are examples of valid functions and invalid functions:

\begin{itemize}
\item \texttt{sin(x)}
\item \texttt{sin(2*x)}
\item \texttt{sin(x**2)}
\item \texttt{exp(x)}
\item \texttt{3*x**x}
\item \texttt{exp(sin(2*x))}
\item \texttt{sinh(x)}
\item \texttt{sin(t)*cos(t)} (\textit{polar plot only})
\end{itemize}