수직 그래프(x=n)

\begin{tikzpicture}
[+preamble]
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
[/preamble]
\begin{axis}[
ticks=none,
xmin=-1,
xmax=5,
ymin=-1,
ymax=5,
axis lines=middle,
xlabel=$w$,
ylabel=$r$,
disabledatascaling]
\draw[line width=0.5mm] (2,0) -- (2,3);
\end{axis}
\end{tikzpicture}