\begin{exercice}[Fonctions définies sur $\mathbb{R}$]
Dresser les tableaux de signes  des fonctions représentées ci-dessous.
\begin{enumerate}
\item 
\begin{center}
  \begin{tikzpicture}[general]
   \draw[quadrillage55] (-3.5,-2) grid (3.5,2);
   \axeX{-3.5}{3.5}{1}
   \axeY{-2}{2}{1}
   \origine
 \draw[epais, color=A1] plot[domain=-3.076:3.5, smooth, samples=100, variable=\x] (\x,-0.25*\x*\x+0.125*\x+0.75);
 \draw (-3.25, 1.75) node[color=A1] {{\boldmath $\mathcal{C}_f$}};
  \end{tikzpicture}
 \end{center}
 
 \item
 \begin{center}
  \begin{tikzpicture}[general, yscale=0.5]
   \draw[quadrillage, ystep=1, xstep=0.5] (-3.5,-9) grid (3.5,2);
   \axeX{-3.5}{3.5}{1}
   \axeY{-9}{2}{1}
   \origine
   \draw[epais, color=C1] plot[domain=-1.237:3.237, smooth, samples=100, variable=\x] (\x,-6+2*\x*\x-4*\x);
\draw (-3.25, 1.5) node[color=C1] {{\boldmath $\mathcal{C}_g$}};
  \end{tikzpicture}
 \end{center}
 
 \item
\begin{center}
  \begin{tikzpicture}[general, xscale=2, yscale=0.5]
   \draw[quadrillage, xstep=0.25] (-1.75,-3) grid (1.75,7);
   \axeX{-1.75}{1.75}{1}
   \axeY{-3}{7}{2,-2, 4, 6}
   \origine
   \draw[epais, color=J1] plot[domain=-0.914:1.636, smooth, samples=100, variable=\x] (\x,2+7*\x*\x*\x*\x-8*\x*\x*\x-5*\x*\x+2*\x);
 \draw (-1.5, 6.5) node[color=J1] {{\boldmath $\mathcal{C}_h$}};
 \end{tikzpicture}
 \end{center}
 
 \item 
 \begin{center}
  \begin{tikzpicture}[general, scale=1]
   \draw[quadrillage55] (-3.5,-3.5) grid (3.5,2.5);
   \axeX{-3.5}{3.5}{1}
   \axeY{-3.5}{2.5}{1}
   \origine
 \draw[epais, color=H1prime] plot[domain=-2.974:2.309, smooth, samples=100, variable=\x] (\x,(0.6*\x*\x*\x+0.6*\x*\x-2.85*\x-1.5);
\draw (-3.25, 2.25) node[color=H1prime] {{\boldmath $\mathcal{C}_m$}};
  \end{tikzpicture}
 \end{center}
\end{enumerate}
\end{exercice}
