\input{preamble-standalone.ltx} \begin{document} % Ex. No. 18 (Section 7.2 : Tangente avec \tkzname{xstep} et \tkzname{ystep} différents de 1) \begin{tikzpicture}[xscale=1.5] \tikzset{tan style/.style={-}} \tkzInit[xmin=0,xmax=800,xstep=100, ymin=0,ymax=1800,ystep=400] \tkzGrid[color=brown,sub,subxstep=50,subystep=200](0,0)(800,1800) \tkzAxeXY \tkzFct[color=red,samples=100,domain = 0:800]% {(1./90000)*\x*\x*\x-(1./100)*\x*\x+(113./36)*\x} \tkzDrawTangentLine[color=blue,kr=300,kl=450,coord](450) \tkzText[draw, color = black,% fill = brown!50, opacity = 0.8](300,1200)% {$f(x)=\dfrac{1}{90000}x^3 -\dfrac{1}{{100}}x^2 +\dfrac{113}{36}x$} \end{tikzpicture} \end{document}