\documentclass[12pt]{book} 
\usepackage{pst-plot}
\usepackage{pgfplots,tikz,amssymb,amsmath}
\usetikzlibrary{datavisualization.formats.functions}
\usepackage{subfigure}
\usepackage{color}
\usepackage{tocbibind}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{graphicx}
\usepackage{xepersian}
\settextfont{XB Zar}
\linespread{1.25}


\begin{document}
 \begin{figure}[htp]
 \begin{tikzpicture}
\begin{axis} [ 
    axis lines=middle,
    inner axis line style={=>},
    xlabel={\large $x$},
    ylabel={\large $y$},
    xticklabel style={inner xsep=.5pt, anchor=north east},
   xtick={0,0.125,...,1.1},
    ytick={-1,0,1},
    xticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=8},
    yticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=1},
    ymin=-1.2,
    ymax=1.2,
    xmin=-0.1,
    xmax=1.2]
\addplot[color=blue,ultra thick] coordinates {
(-0.1,0)
(0,0)
        (0,1)
        (1/8,1)
        (1/8,-1)
        (2/8,-1)
        (2/8,0)
        (1.125,0)
    };
    \end{axis}
    
      \end{tikzpicture}
      \centering
\caption{\small{$ \psi_{2,0}=h_5(x)$}}
\end{figure}

 \begin{figure}[htp]
  \begin{tikzpicture}
\begin{axis}[ 
    axis lines=middle,
    inner axis line style={=>},
    xlabel={\large $x$},
    ylabel={\large $y$},
    xticklabel style={inner xsep=.5pt, anchor=north east},
   xtick={0,0.125,...,1.1},
    ytick={-1,0,1},
    xticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=8},
    yticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=1},
    ymin=-1.2,
    ymax=1.2,
    xmin=-0.1,
    xmax=1.2]
\addplot[color=blue,ultra thick] coordinates {
(-0.1,0)
(2/8,0)
        (2/8,1)
        (3/8,1)
        (3/8,-1)
        (4/8,-1)
        (4/8,0)
        (1.125,0)
    };
    \end{axis}
      \end{tikzpicture}
\centering
\caption{\small{  $ \psi_{2,1}=h_6(x)$}}
\end{figure}


 \begin{figure}[htp]
 \begin{tikzpicture}
\begin{axis}[ 
    axis lines=middle,
    inner axis line style={=>},
    xlabel={\large $x$},
    ylabel={\large $y$},
    xticklabel style={inner xsep=.5pt, anchor=north east},
   xtick={0,0.125,...,1.1},
    ytick={-1,0,1},
    xticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=8},
    yticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=1},
    ymin=-1.2,
    ymax=1.2,
    xmin=-0.1,
    xmax=1.2]
\addplot[color=blue,ultra thick] coordinates {
(-0.1,0)
(4/8,0)
        (4/8,1)
        (5/8,1)
        (5/8,-1)
        (6/8,-1)
        (6/8,0)
        (1.125,0)
    };
    \end{axis}
      \end{tikzpicture}
      \centering
\caption{\small{$ \psi_{2,2}=h_7(x)$}}
\end{figure}

 \begin{figure}[htp]
  \begin{tikzpicture}
\begin{axis}[ 
    axis lines=middle,
    inner axis line style={=>},
    xlabel={\large $x$},
    ylabel={\large $y$},
    xticklabel style={inner xsep=.5pt, anchor=north east},
   xtick={0,0.125,...,1.1},
    ytick={-1,0,1},
    xticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=8},
    yticklabel style={/pgf/number format/.cd,frac,frac TeX=\ds\frac,frac denom=1},
    ymin=-1.2,
    ymax=1.2,
    xmin=-0.1,
    xmax=1.2]
\addplot[color=blue,ultra thick] coordinates {
(-0.1,0)
(6/8,0)
        (6/8,1)
        (7/8,1)
        (7/8,-1)
        (8/8,-1)
        (8/8,0)
        (1.125,0)
    };
    \end{axis}
      \end{tikzpicture}
\centering
\caption{\small{  $ \psi_{2,3}=h_8(x)$}}
\end{figure}

\end{document}