\documentclass{article}
\usepackage{amsmath}
\usepackage{caption,tikz}
\usepackage{xepersian}
\settextfont{Yas}
\setdigitfont{Yas}
\begin{document}
\begin{figure}[htp]\centering
\begin{tikzpicture}[scale=0.19,yscale=10,xscale=0.6,smooth]
\draw[->] (0,0) -- (58,0) node[right] {$x$};
\draw[->] (0,0) -- (0,2.8) node[above] {$C(x)$};
\foreach \pos in {50,60,70,80,90}
\draw[shift={(\pos,0)},xshift=-420mm] (0pt,0pt) -- (0pt,2pt) node[below,xshift=1,yshift=-2mm] {$\pos$};
%\foreach \pos in {0.5,1}
%\draw[shift={(0,\pos)},yshift=2.5mm] (0pt,0pt) -- (20pt,0pt) node[left,yshift=1.4mm] {$\pos$};
\foreach \y  in {2}{
     \pgfmathsetmacro {\ytext} {int(\y /2)}
        \draw (1pt,\y cm) -- (-1pt,\y cm) node[left]  {$\ytext$};
        \draw (-1pt,1) -- (0pt,1) node[left]  {$0.5$};
      }
      \draw (0,1)--(-0.6,1);
      \draw (0,2)--(-0.6,2);
\draw[xshift=-20mm,yshift=0mm,color=red] plot coordinates{(5,0.05)(10,0)(15,0.05)(20,0.17)(25,0.4)(30,1)(35,1.45)(40,1.8)(45,1.95)(50,2)(60,2)};
\draw[dashed](0,1) --(29,1);
\end{tikzpicture}
\caption{نمودار تابع عضویت $S$شکل مربوط به پیری  در مثال \ref{ex2.2.5}}
\label{fig2.2.6}
\end{figure}
\end{document}