The plane is equipped with an orthogonal coordinate system.\\
We consider a function $f$ defined and differentiable on $\mathbb{R}$. We denote $f^{\prime}$ its derivative function. The representative curve of the derivative function $f^{\prime}$ is given.

In this part, results will be obtained by graphical reading of the representative curve of the derivative function $f^{\prime}$. No justification is required.

\begin{enumerate}
  \item Give the direction of variation of the function $f$ on $\mathbb{R}$. Use approximate values if necessary.
  \item Give the intervals on which the function $f$ appears to be convex.
\end{enumerate}