\documentclass{book}
\usepackage{tikz}
\usepackage{amsmath}
\usepackage{pgfplots}
\usepackage{xcolor}
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
%\usepackage[paperwidth=\maxdimen, paperheight=\maxdimen]{geometry}
%\usepackage{xepersian}

\begin{document}
\begin{flushright}
\begin{tikzpicture}[scale=1]

%\draw[help lines] (-4,-4) grid (4,4);

\node (A) at (-2,0) [left] {$X$};
\node (B) at (2,0) [ above = 1mm, right ] {$Y$};
\node (C) at (0,2) {$X_1:Y_1\hbox{یبی}$};

\draw [very thick] (-2,0) -- (2,0);

\draw [very thick] (.2,1.8) -- (2,0);

\draw [very thick](1.25,1.5) arc (120:210:15mm) ;

\end{tikzpicture}
\end{flushright}
\end{document}