\begin{exercice*}[\ExerciceRefMethode{methode4A1}]
\label{ex20A1}
  Étudier les variations de chacune des fonctions du second degré
  définies sur $\R$ par les expressions suivantes.
  \begin{enumerate}
  \item $f_1\left(x\right)={\left(x-1\right)}^2+10$
  \item $f_2\left(x\right)=-2{\left(x-5\right)}^2+2$
  \item $f_3\left(x\right)=3x^2+\dfrac{1}{3}$
  \item $f_4\left(x\right)=-2{\left(x+3\right)}^2-5$
  \end{enumerate}
\end{exercice*}
\begin{corrige}
  \begin{enumerate}
  \item $a > 0$

     {\centering
      \begin{tikzpicture}[scale=0.7,general]
        \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
        colorV=H4, colorL=H4, colorT=A4]
        {$x$/1, $f$/2}
        {$-\infty$,$1$,$+\infty$}
        \tkzTabVar{+/, -/10 , +/}
      \end{tikzpicture}
      \par}

  \item $a < 0$

     {\centering
      \begin{tikzpicture}[scale=0.7,general]
        \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
        colorV=H4, colorL=H4, colorT=A4]
        {$x$/1, $f$/2}
        {$-\infty$,$5$,$+\infty$}
        \tkzTabVar{-/, +/2 , -/}
      \end{tikzpicture}
      \par}

  \item $a > 0$

     {\centering
      \begin{tikzpicture}[scale=0.7,general]
        \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
        colorV=H4, colorL=H4, colorT=A4]
        {$x$/1, $f$/2}
        {$-\infty$,$0$,$+\infty$}
        \tkzTabVar{+/, -/$-5$ , +/}
      \end{tikzpicture}
      \par}

  \item $a < 0$

     {\centering
      \begin{tikzpicture}[scale=0.7,general]
        \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
        colorV=H4, colorL=H4, colorT=A4]
        {$x$/1, $f$/2}
        {$-\infty$,$-3$,$+\infty$}
        \tkzTabVar{-/, +/$-5$ , -/}
      \end{tikzpicture}
      \par}
  \end{enumerate}
\end{corrige}