How to draw a vertical dashed line?

Question

I want to draw a vertical dashed line (1,0) -- (1,3) but it does not work..
documentclass{article}
usepackage{tikz}
usetikzlibrary{arrows}
usepackage{pgfplots}

usepackage[utf8]{inputenc}
pgfplotsset{width=7cm,compat=1.9}

begin{document}

begin{tikzpicture}
begin{axis}[
  axis x line=center,
  axis y line=center,
   xlabel = {$alpha$},
    ylabel = {$h(alpha)$},
  xlabel style={ right},
  ylabel style={above },
]

addplot [
    domain=-1.5:1.5, 
    samples=1000, 
    color=blue,
    ]
    {1*x + 1*x^2};

end{axis}

draw[dashed] (1,0) -- (1,3);

end{tikzpicture}

end{document}

Ivan · Answer

Put this inside the axis environment:
draw [dotted,->] (axis cs:1,0) -- (axis cs:1,3);

Zarko · Answer

With use of the recent LaTeX installation and recent version pgfplots package (yours is very old, it is time to upgrade it):

documentclass{article}
usepackage{pgfplots} % it loads tikz too
usetikzlibrary{arrows}
pgfplotsset{width=7cm,compat=1.17} % <----

begin{document}
    begin{tikzpicture}
begin{axis}[
  axis lines=center,
   xlabel = {$alpha$},
   ylabel = {$h(alpha)$},
  xlabel style={ right},
  ylabel style={above },
            ]
addplot +[domain=-1.5:1.5, samples=100, thick, no marks]
    {1*x + 1*x^2};
draw[dashed] (1,0) -- (1,3);  % <---
end{axis}
    end{tikzpicture}
end{document}

How to draw a vertical dashed line?

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