$$ \begin{array}{c|ccccccccc}
x & -\infty & & -\sqrt{2} & & 0 & & \sqrt{2} & & +\infty \\
\hline
y’ & & – & 0 & + & 0 & – & 0 & + & \\
\hline
y & & \searrow & 5 & \nearrow & 9 & \searrow & 5 & \nearrow &
\end{array} $$
————-
\begin{tikzpicture}
\tkzTabInit[nocadre,lgt=1,espcl=2.5]
{$x$/0.7,$y’$/0.7,$y$/2}{$-\infty$,$-2$,$+\infty$}
\tkzTabLine{,-,d,-,}
\tkzTabVar{+/$1$,-D+/$-\infty$/$+\infty$,-/$1$}
\end{tikzpicture}