\documentclass[a4paper,10pt]{article}
\usepackage{myXsim}

\title{Autour de la notion de convexité}
\tribe{Terminale ES}
\date{Octobre 2019}

\pagestyle{empty}

\newcommand\lesgraphiques{%
    \begin{minipage}{0.5\textwidth}
        \includegraphics[scale=0.3]{./fig/C_f_QCM_liban2018}
        \begin{center}
            Représentation graphique de la fonction $f$ 
        \end{center}
    \end{minipage}
    \hfill
    \begin{minipage}{0.5\textwidth}
        \begin{tikzpicture}[xscale=0.8, yscale=]
            \tkzInit[xmin=-5,xmax=5,xstep=1,
            ymin=-4,ymax=3,ystep=1]
            \tkzGrid
            \tkzAxeXY
            \tkzFct[domain = -5:5,color=red,very thick]%
            {0.25*x**4-1.5*x**2-x+1}
            \draw (3, 2) node [color=black, below right] {$\matcal{C}_g$}
        \end{tikzpicture}
        \begin{center}
            Représentation graphique de la fonction $g$ 
        \end{center}
    \end{minipage}

    \vfill

    \begin{minipage}{0.3\textwidth}
        \begin{tikzpicture}[xscale=0.5, yscale=1]
            \tkzInit[xmin=0,xmax=10,xstep=1,
            ymin=0,ymax=3,ystep=1]
            \tkzGrid
            \tkzAxeXY
            \tkzFct[domain = 0:10,color=red,very thick]%
            {(2*x+1)*2.7**(-0.5*x)}
            \draw (9, 1) node [color=black, below] {$\matcal{C}_h$}
        \end{tikzpicture}
    \end{minipage}
    \hfill
    \begin{minipage}{0.3\textwidth}
        \begin{tikzpicture}[xscale=0.5, yscale=1]
            \tkzInit[xmin=0,xmax=10,xstep=1,
            ymin=-1,ymax=2,ystep=1]
            \tkzGrid
            \tkzAxeXY
            \tkzFct[domain = 0:10,color=red,very thick]%
            {(-x+1.5)*2.7**(-0.5*x)}
            \draw (9, 1) node [color=black, below] {$\matcal{C}_{h'}$}
        \end{tikzpicture}
    \end{minipage}
    \hfill
    \begin{minipage}{0.3\textwidth}
        \begin{tikzpicture}[xscale=0.5, yscale=1]
            \tkzInit[xmin=0,xmax=10,xstep=1,
            ymin=-2,ymax=1,ystep=1]
            \tkzGrid
            \tkzAxeXY
            \tkzFct[domain = 0:10,color=red,very thick]%
            {(0.5*x-1.75)*2.7**(-0.5*x)}
            \draw (9, 1) node [color=black, below left] {$\matcal{C}_{h''}$}
        \end{tikzpicture}
    \end{minipage}
    \begin{center}
        Représentations graphiques de la fonction $h$  et de ses dérivées
    \end{center}
}
\begin{document}

\lesgraphiques
\vfill
\lesgraphiques

\end{document}