% !TeX TXS-program:compile = txs:///pdflatex

\documentclass[margin=5mm]{standalone}
\usepackage[nonpgfplots]{tkz-grapheur}

\begin{document}

\begin{GraphiqueTikz}[x=1.75cm,y=1.75cm,Xmin=-1,Xmax=5.5,Ymin=-1,Ymax=2.5]
	%axes et grille
	\TracerAxesGrilles[Police=\small,Elargir=0mm,Grille=false,Origine]{1}{}
	%tracés
	\TracerCourbe[Couleur=red,Debut=0.1]{ln(x)}
	\TracerCourbe[Couleur=blue]{1/1.85*(x-1.85)+1*ln(1.85)}
	\TracerCourbe[Couleur=olive]{1*ln(1.85)}
	\draw[pfltrait] (0,{1*ln(1.85)}) rectangle++ (3pt,-3pt) ;
	\draw[dashed] (1.85,0) node[below] {$x_0$} --++ (0,{1*ln(1.85)}) ;
	%textes
	\PlacerTexte[Position=below left]{(\pflxmax,0)}{$x$}
	\PlacerTexte[Position=below left]{(0,\pflymax)}{$y$}
	\PlacerTexte[Couleur=red,Position=below]{(5,1.5)} {$\mathcal{C}$}
	\PlacerTexte[Couleur=blue,Position=below]{(-0.75,-0.5)}{$T$}
	\PlacerTexte[Position=above left]{(0,{1*ln(1.85)})}{$B$}
	\MarquerPts[Style=x]{(1.85,{1*ln(1.85)})/$M$/above,(0,{-1+ln(1.85)})/$A$/below right}
\end{GraphiqueTikz}

%\begin{tikzpicture}[x=1.75cm,y=1.75cm,xmin=-1,xmax=5.5,ymin=-1,ymax=2.5]
%	\CourbeTikz[thick,red,samples=250]{ln(\x)}{0.1:5.5}
%	\CourbeTikz[thick,blue,samples=2]{1/1.85*(\x-1.85)+1*ln(1.85)}{\xmin:\xmax}
%	\CourbeTikz[thick,olive,samples=2]{1*ln(1.85)}{\xmin:\xmax}
%	\draw[semithick]  pic{PLdotcross=3pt/0} node[] {} ;
%	\draw[semithick] pic{PLdotcross=3pt/0} node[below right] {} ;
%\end{tikzpicture}


\end{document}