%!TEX pdflatex

\documentclass[a4paper]{article}
\usepackage[margin=1cm]{geometry}
\usepackage{tkz-grapheur}
\usepackage{postit}
\usepackage{lipsum}

\begin{document}

\lipsum[1]

\medskip

\begin{GraphiqueTikz}%
	[x=0.9cm,y=0.425cm,Xmin=4,Xmax=20,Origx=4,
	Ymin=40,Ymax=56,Ygrille=2,Ygrilles=1,Origy=40,remember picture]
	\TracerAxesGrilles[Elargir=2.5mm,Police=\small]{4,5,...,20}{40,42,...,56}
	%définition de la fonction + tracé de la courbe
	\TracerCourbe[Couleur=red,Debut=5,Fin=19]{-2*x+3+24*log(2*x)}
	\coordinate (ESSAI-1) at (\pflxmax,\pflymax) ;
\end{GraphiqueTikz}

\begin{tikzpicture}[remember picture,overlay]
	\draw ([yshift=-1cm]ESSAI-1.center) node {\begin{PostIt}[Rendu=tikz]\lipsum[1][1-2]\end{PostIt}} ;
\end{tikzpicture}

\lipsum[2-4]

\begin{tikzpicture}[remember picture,overlay]
	\draw ([xshift=7cm,yshift=-15cm]current page.north west) node {\begin{PostIt}[Rendu=tikz,Inclinaison=15,Attache=Non]\lipsum[1][1-2]\end{PostIt}} ;
	\draw ([xshift=1.25cm,yshift=3.75cm]current page.south) node {\begin{PostIt}[Rendu=tikz,Inclinaison=-10,Attache=Non]\lipsum[3][1-2]\end{PostIt}} ;
\end{tikzpicture}

\end{document}