\subsection{cosh}
\label{labcosh}
\noindent Name: \textbf{cosh}\\
\phantom{aaa}the hyperbolic cosine function.\\[0.2cm]
\noindent Library names:\\
\verb|   sollya_obj_t sollya_lib_cosh(sollya_obj_t)|\\
\verb|   sollya_obj_t sollya_lib_build_function_cosh(sollya_obj_t)|\\
\verb|   #define SOLLYA_COSH(x) sollya_lib_build_function_cosh(x)|\\[0.2cm]
\noindent Description: \begin{itemize}

\item \textbf{cosh} is the usual hyperbolic function: $\cosh(x) = \frac{e^x + e^{-x}}{2}$.

\item It is defined for every real number $x$.
\end{itemize}
See also: \textbf{acosh} (\ref{labacosh}), \textbf{sinh} (\ref{labsinh}), \textbf{tanh} (\ref{labtanh}), \textbf{exp} (\ref{labexp})
