\documentclass{standalone} \usepackage{/media/documents/Cours/Prof/Enseignements/tools/style/base} \usepackage{tkz-fct} \usepackage{tikz} \begin{document} \begin{tikzpicture}[xscale=0.6, yscale=0.4] %\repere{-0.5}{12.9}{-0.5}{15.9} %\draw[red] plot[samples=200,domain=-1:2] function {x**2}; \tkzInit[xmin=0,xmax=130, ymin=0,ymax=400, xstep=10,ystep=20] \tkzAxeX[thick, poslabel=right,label=] \tkzAxeY[thick, poslabel=above,label=] \tkzDrawX[label={\textit{Prix d'une visseuse}},below= -12pt] \tkzDrawY[label={\textit{Quantité}}, below=-10pt] \tkzGrid \tkzFct[domain=0:130,color=blue, very thick]{-0.0001*\x*\x + 2.3*\x} %\tkzText[above right,color=blue](24,655){$\mathcal{C}_C$} \tkzFct[domain=0:130,color=red, very thick]{0.01*\x*\x - 2.6*\x + 350} %\tkzText[above ,color=red](24,750){$\mathcal{C}_R$} \end{tikzpicture} \end{document}