我怎样才能在 PGFPlots 中支撑 x 轴？

Question

我不知道为什么，但这个命令\draw似乎在我的代码中不起作用。理想情况下，我希望看到以下内容：

我的代码是：

\begin{tikzpicture}
\begin{axis}[
    axis lines = left,
    xmin=0,
    xmax=4,
    xlabel = $z$,
    ymin=0,
    ymax=3,
    ylabel = {$\pi(w,r,z)$}
]
\
\addplot[color=green]{{0.0018741*(x^6.66667)}};
\addlegendentry{$\pi(w,r,z)$};
\addplot[color=red]
{{1}};\addlegendentry{$w$};
 \addplot[mark=*] coordinates {(2.55,1)} node[pin=150:{$\pi(w,r,\bar{z})=w$}]{} ;
  \addplot[mark=*] coordinates {(2.55,0)} node[pin=150:{$\bar{z}$}]{} ;
 \addplot[dashed] coordinates {(2.55,0) (2.55,1)};
\end{axis}
\end{tikzpicture}

Answer 1

欢迎使用 TeX-SE！将来请考虑提供以以下代码开头\documentclass和结尾的完整代码：\end{document}

\documentclass[tikz,border=3.14mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16,width=10cm}
\usetikzlibrary{decorations.pathreplacing}
\begin{document}
\begin{tikzpicture}
 \begin{axis}[axis lines=left,xmin=0,xmax=4,xlabel=$z$,ymin=0,ymax=3,ylabel={$\pi(w,r,z)$}]
  \addplot[color=green]{{0.0018741*(x^6.66667)}}; 
  \addlegendentry{$\pi(w,r,z)$}; 
  \addplot[color=red] {{1}};
  \addlegendentry{$w$}; 
  \addplot[mark=none] coordinates {(2.55,1)} node[pin=150:{$\pi(w,r,\bar{z})=w$}]{};
  \addplot[mark=none] coordinates {(2.55,0)} node[pin=150:{$\bar{z}$}]{} ; 
  \addplot[dashed] coordinates {(2.55,0) (2.55,1)}; 
  \path (0,0) coordinate (O) (2.5,0) coordinate (M) (4,0) coordinate (R);  
 \end{axis} 
 \draw[decorate,decoration={brace,raise=2.5em}] (M) -- (O) node[midway,below=2.6em] {text A};
 \draw[decorate,decoration={brace,raise=2.5em}] (R) -- (M) node[midway,below=2.6em] {text B};
\end{tikzpicture}
\end{document}