
\begin{tikzpicture}[line cap=round,line join=round,>=triangle 45,x=0.5cm,y=0.5cm]
\begin{axis}[
x=0.5cm,y=0.5cm,
axis lines=middle,
ymajorgrids=true,
xmajorgrids=true,
xmin=-5.5,
xmax=9.5,
ymin=-3.8,
ymax=4.5,
xtick={-7,-6,...,9},
ytick={-5,-4,...,4},]
\clip(-5.5,-3.8) rectangle (9.5,4.5);
     % courbe par contraintes manuelles 
\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=-6.0:-4.0)] plot (\x,{(-0.025*(\x)^3+-0.465*(\x)^2+-0.75*(\x)+2.84)/1.0}););\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=-4.0:-2.0)] plot (\x,{(-0.3075*(\x)^3+-3.21*(\x)^2+-9.15*(\x)+-4.92)/1.0}););\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=-2.0:1.0)] plot (\x,{(0.08556*(\x)^3+-0.07667*(\x)^2+-1.33333*(\x)+1.32444)/1.0}););\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=1.0:3.0)] plot (\x,{(0.1925*(\x)^3+-0.8475*(\x)^2+-0.1125*(\x)+0.7675)/1.0}););\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=3.0:5.0)] plot (\x,{(-0.14*(\x)^3+2.04*(\x)^2+-8.46*(\x)+8.8)/1.0}););\draw [samples=50,rotate around={0.:(0.,0.)},xshift=0.cm,yshift=0.cm,line width=0.5pt,domain=5.0:8.0)] plot (\x,{(0.01185*(\x)^3+-0.47111*(\x)^2+5.26222*(\x)+-16.01481)/1.0}););
\begin{scriptsize}
\draw [color=black] (8.,2.)-- ++(-2.5pt,0 pt) -- ++(5.0pt,0 pt) ++(-2.5pt,-2.5pt) -- ++(0 pt,5.0pt);
\end{scriptsize}
\end{axis}
\end{tikzpicture}