我正在尝试绘制一些函数，但是我遇到了一个问题，即不同的函数得到相同的输出
以下是代码：
\documentclass[a4paper]{article}
\usepackage{pgfplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] plot gnuplot{((0.2)^(1/10)+(1-0.2)^(1/10)*x^(1-1/10))/(0.999^(1/10)*(0.999^(1-1/10)*0.2^(1/10)+(1-0.2)^(1/10)*x^(1-1/10))) -1)};
\addlegendentry{$\xi=1/10$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot
{((0.2)^(1/2)+(1-0.2)^(1/2)*x^(1-1/2))/(0.999^(1/2)*(0.999^(1-1/2)*0.2^(1/2)+(1-0.2)^(1/2)*x^(1-1/2))) -1)};
\addlegendentry{$\xi=1/2$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot
{((0.2)^(99/100)+(1-0.2)^(99/100)*x^(1-99/100))/(0.999^(99/100)*(0.999^(1-99/100)*0.2^(99/100)+(1-0.2)^(99/100)*x^(1-99/100))) -1)};
\addlegendentry{$\xi=99/100$}
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}
在编译时，我还短暂地看到了“第 2 行意外或无法识别的标记”消息，但我不知道如何修复它。我非常感谢任何帮助。
答案1
似乎gnuplot无法将分数识别为浮点数。因此，请在分数末尾放置一个点：
\documentclass[a4paper]{article}
\usepackage{pgfplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] plot gnuplot{((0.2)^(1/10.)+(1-0.2)^(1/10.)*x^(1-1/10.))/(0.999^(1/10.)*(0.999^(1-1/10.)*0.2^(1/10.)+(1-0.2)^(1/10.)*x^(1-1/10.)))-1};
\addlegendentry{$\xi=1/10$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot{((0.2)^(1/2.)+(1-0.2)^(1/2.)*x^(1-1/2.))/(0.999^(1/2.)*(0.999^(1-1/2.)*0.2^(1/2.)+(1-0.2)^(1/2.)*x^(1-1/2.)))-1};
\addlegendentry{$\xi=1/2$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot{((0.2)^(99/100.)+(1-0.2)^(99/100.)*x^(1-99/100.))/(0.999^(99/100.)*(0.999^(1-99/100.)*0.2^(99/100.)+(1-0.2)^(99/100.)*x^(1-99/100.)))-1};
\addlegendentry{$\xi=99/100$}
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}
或者用小数值替换分数：
\documentclass[a4paper]{article}
\usepackage{pgfplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] plot gnuplot{((0.2)^(0.1)+(1-0.2)^(0.1)*x^(1-0.1))/(0.999^(0.1)*(0.999^(1-0.1)*0.2^(0.1)+(1-0.2)^(0.1)*x^(1-0.1)))-1};
\addlegendentry{$\xi=1/10$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot{((0.2)^(0.5)+(1-0.2)^(0.5)*x^(1-0.5))/(0.999^(0.5)*(0.999^(1-0.5)*0.2^(0.5)+(1-0.2)^(0.5)*x^(1-0.5)))-1};
\addlegendentry{$\xi=1/2$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture} %[scale=0.7]
\begin{axis}[title style={yshift=-1ex,},
title={$a=0.2$},
xlabel style={align=center}, xlabel=$p_2$,
ylabel = {$\Delta x_1^{a,b}/x_1^{a,b}$}, xmin=0, xmax=2,
ymin=0,ymax=0.003,
legend style={legend pos=north west,legend cell align={left}}, enlargelimits=false, width={10cm},height={8cm}, xtick distance=0.5,
ytick distance=0.0005,
restrict y to domain=0:0.003,samples=500]
\addplot[mark=none, color=black, dashed] gnuplot{((0.2)^(0.99)+(1-0.2)^(0.99)*x^(1-0.99))/(0.999^(0.99)*(0.999^(1-0.99)*0.2^(0.99)+(1-0.2)^(0.99)*x^(1-0.99)))-1};
\addlegendentry{$\xi=99/100$}
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}
