使用 tikz 包绘制曲线

Question

我正在尝试绘制下图所示的曲线。

有人可以帮我用 TikZ 或 PSTricks 画图吗？

Answer 1

如果你知道你的图表的功能，那么最好的选择就是 pgfplots：

\documentclass[border=1cm]{standalone}

\usepackage{tikz,pgfplots}
\pgfplotsset{compat=1.12}
\usepackage{upgreek}

\begin{document}

\begin{tikzpicture}
  \begin{axis}[
    axis lines=middle,
    xlabel=$\uptau 1$,
    every axis x label/.style={at={(current axis.right of origin)},anchor=west},
    ylabel=$\uptau 2$,
    every axis y label/.style={at={(current axis.above origin)},anchor=south},
    xmin=-0.5,
    xmax=10.5,
    ymin=-30,
    ymax=5,
    yticklabels={,,}, % removes ticklabels from y axis
    ytick style={draw=none}, % removes ticks from y axis
    xticklabels={,,}, % removes ticklabels from y axis
    xtick style={draw=none} % removes ticks from y axis
    ]
        \addplot+[orange,no marks,domain=-1:10,samples=100, thick] {(-x/2)+1} node[midway,yshift=0.5cm] {$f1 (\uptau 1)$};
        \addplot+[blue,no marks,domain=-1:10,samples=100, thick] {(-x/2)-10} node[midway,yshift=0.5cm] {$f2 (\uptau 2)$};     
  \end{axis}

\end{tikzpicture}

\end{document}