\documentclass[a4paper,12pt]{article}
\usepackage{pstricks,pstricks-add,pst-3dplot,pst-func,fourier,fullpage}
\usepackage{amsmath}
\usepackage{graphicx}
%\usepackage{xepersian}
%\settextfont[Scale=1]{XB Niloofar}
%\setlatintextfont[Scale=1]{Linux Libertine}
%\setdigitfont[Scale=1]{XB Zar}
%\title{رسم توابع با \lr{\textsf{PSTricks}}}
%\author{وفا خلیقی}

\begin{document}
\begin{pspicture}(-0.5,-0.5)(5,5)
\psset{algebraic=true}
%\psaxes{->}(0,0)(-0.5,-0.5)(5,5)
\uput[l](0,5){P}
\uput[r](5,0){V}
\psline{->}(-0.5,0)(5,0)
\psline{->}(0,-0.5)(0,5)
\psplot[linewidth=2pt]{1}{4}{x^(0.5) +1}
\psline(1,0)(1,2)
\psline(4,0)(4,3)
\uput[l](2.5,1){S}
\pscustom[fillstyle=hlines]{%
%\
\psline(1,0)(1,2)
\psplot{1}{4}{x^(0.5) +1}
%
}
\pspolygon[fillstyle=hlines](1,0)(4,3)(4,0)
\uput[l](1.75,4){$ \Rightarrow\clubsuit $}
\uput[l](4.5,4){$ \Rightarrow\clubsuit $}
\end{pspicture}

\end{document}