# Plot dash lines on plot (specifying coordinates)

I'd like to get the plot in the following figure (without grid):

Until now I got only axis+point:

\usepackage{pgfplots}
\pgfplotsset{width=10cm,compat=1.9}

\begin{tikzpicture}
\begin{axis}
\end{axis}
\end{tikzpicture}


Thank you very much for your time.

You mean something like the following?

% used PGFPlots v1.15
\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\pgfplotsset{
compat=1.11,
}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
xmin=0,     xmax=8,
ymin=0,     ymax=8,
xlabel={$x$},
ylabel={$y$},
axis lines=center,
xtick={1,2},
ytick={1,2},
]

• @GennaroArguzzi, because then the TikZ coordinates have to be preceded by axis cs:, i.e. you have write \draw [dashed,help lines] (axis cs:0,2) -| (axis cs:2,0);. – Stefan Pinnow Nov 5 '17 at 15:08