\subsection{cos}
\label{labcos}
\noindent Name: \textbf{cos}\\
\phantom{aaa}the cosine function.\\[0.2cm]
\noindent Library names:\\
\verb|   sollya_obj_t sollya_lib_cos(sollya_obj_t)|\\
\verb|   sollya_obj_t sollya_lib_build_function_cos(sollya_obj_t)|\\
\verb|   #define SOLLYA_COS(x) sollya_lib_build_function_cos(x)|\\[0.2cm]
\noindent Description: \begin{itemize}

\item \textbf{cos} is the usual cosine function.

\item It is defined for every real number $x$.
\end{itemize}
See also: \textbf{acos} (\ref{labacos}), \textbf{sin} (\ref{labsin}), \textbf{tan} (\ref{labtan})
