% arara: xelatex: { options: [ '-output-driver', 'xdvipdfmx -i dvipdfmx-unsafe.cfg -E -q' ] }
\documentclass[11pt]{report}
\usepackage{pst-intersect,pst-plot,mathtools}% ,
\begin{document}
\begin{pspicture}(-2,-2)(8,8)
\psaxes[labelFontSize=\scriptstyle,ticksize=0 4pt]{->}(0,0)(-2,-2)(8,8)[$M$,-90][$Y$,0]
\psset{linewidth=1.5pt,algebraic}
\pssavepath[linecolor=green]{A}{\psplot{-0.5}{8}{4*(1-1.2^(-3*x+1))}}
\psline[linecolor=red](-2,4)(8,4) \uput[90](7,4){$Y=\dfrac{A}{\alpha+d}$}
\end{pspicture}