\begin{exercice}Pour chacune des courbes suivantes, établir le tableau de variations des fonctions représentées.\\% sur $\left]-5;5\right[$.\\ 
%\vspace{0.2em}

%\vspace{2em}
%\begin{center}
  \begin{tikzpicture}[general, scale=0.78]
 \draw[quadrillage55] (-2.5,-2.5)grid (2.5,2.5);
 \axeX{-2.5}{2.5}{1}
 \axeY{-2.5}{2.5}{1}
 \origine
 \draw[smooth, epais, color=C1] plot coordinates {(-2.5,2)(-1.5,0)(-0.5,-1)(1,2)(2.5,1)};
\draw[color=A1, epais] (-2,2) node[draw, circle] {$a$};
\end{tikzpicture}
\hfill
\begin{tikzpicture}[general, scale=0.78]
 \draw[quadrillage55] (-2.5,-2.5)grid (2.5,2.5);
 \axeX{-2.5}{2.5}{1}
 \axeY{-2.5}{2.5}{1}
 \origine
 \draw[smooth, epais, color=C1] plot coordinates {(-2.5,-1)(-1,2)(0,0)(2.5,2)};
\draw[color=A1, epais] (-2,2) node[draw, circle] {$b$};
\end{tikzpicture}
%\vspace{1em}
\begin{tikzpicture}[general, scale=0.78]
 \draw[quadrillage55] (-2.5,-2.5)grid (2.5,2.5);
 \axeX{-2.5}{2.5}{1}
 \axeY{-2.5}{2.5}{1}
 \origine
 \draw[smooth, epais, color=C1] plot coordinates {(-2.5,-1)(0,1)(2.5,2)};
\draw[color=A1, epais] (-2,2) node[draw, circle] {$c$};
\end{tikzpicture}
%\end{center}
\hfill
\begin{tikzpicture}[general, scale=0.78]
 \draw[quadrillage55] (-2.5,-2.5)grid (2.5,2.5);
 \axeX{-2.5}{2.5}{1}
 \axeY{-2.5}{2.5}{1}
 \origine
 \draw[smooth, epais, color=C1] plot coordinates {(-2.5,2)(-2,1)(-1,1.5)(0,0.5)(2.5,2)};
\draw[color=A1, epais] (-2,2) node[draw, circle] {$d$};
\end{tikzpicture}
%\end{center}
\end{exercice}
