tikzpicture我正在尝试使用“LaTeX -> PS”模式绘制这张图片：
但是，我无法绘制从12.802到的函数图形12.806，因为这些数字对于 PGFPlots 来说太小了。
作为参考，我的想法和源代码来自带有放大镜的情节，其中有一个不同的情节，所以我们需要创建一个plotbox在序言中调用的框，然后在tikzpicture情节环境中使用它。
这是我目前所做的：
\documentclass{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\newsavebox\plotbox % To create a magnifying glass. From https://tex.stackexchange.com/a/267834/152550
\begin{lrbox}{\plotbox}
\begin{tikzpicture}
\begin{axis} [
width=3.5cm,
height=3.5cm,
axis on top,
axis lines = center,
xticklabel style = {font=\tiny},
yticklabel style = {font=\tiny},
xlabel = $t$,
ylabel = $f(t)+g(t)$,
xtick={12.802,12.806},
xticklabels={$12.802$,$12.806$},
ytick={-7.006,-6.994},
yticklabels={$-7.006$,$-6.994$},
ymin=-6.994,
ymax=-7.006,
]
\addplot[very thick,red,smooth,samples=201,variable=t,domain=12.802:12.806] {5*sin((2*t-pi/3) r)-8*cos((2*t+pi/6) r)};
\addplot[blue,smooth,samples=201,variable=t,domain=12.802:12.806] {13*sin((2*t+5.24) r)};
\end{axis}
\end{tikzpicture}%
\end{lrbox}
\begin{document}
\begin{center}
\begin{tikzpicture}
\begin{axis} [
axis on top,
axis lines = center,
axis equal image,
xticklabel style = {font=\tiny},
yticklabel style = {font=\tiny},
xlabel = $t$,
ylabel = $f(t)+g(t)$,
ymin=-13,
ymax=13,
xtick={-13,13},
xticklabels={$-13$,$13$},
ytick={-13,13},
yticklabels={$-13$,$13$},
legend pos=outer north east,
legend style={cells={align=left}},
legend cell align={left},
clip=false
]
\addplot[very thick,red,smooth,samples=201,variable=t,domain=-13:13] {5*sin((2*t-pi/3) r)-8*cos((2*t+pi/6) r)};
\addlegendentry{\(5\sin(2t-\pi/3)-8\cos(2t+\pi/6)\)}
\addplot[blue,smooth,samples=201,variable=t,domain=-13:13] {13*sin((2*t+5.24) r)};
\addlegendentry{\(13\sin(2t+5.24)\)}
% Magnifying glass
\coordinate (spyanchor) at (axis cs:12.804,-7);
\node[circle,draw,inner sep=0pt] at (axis cs:26,-2) (spyplot) {\usebox\plotbox};
\node[circle,draw,inner sep=5pt] at (spyanchor) (spynode) {};
\draw (spyplot) -- (spynode);
\end{axis}
\end{tikzpicture}
\end{center}
\end{document}
如您所见，大圆和轴不在中心，即：
答案1
我会用spy。
\documentclass{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\usetikzlibrary{spy}
\begin{document}
\begin{center}
\begin{tikzpicture}[spy using outlines={circle, magnification=7, size=2cm, connect spies}]
\begin{axis} [
axis on top,
axis lines = center,
axis equal image,
xticklabel style = {font=\tiny},
yticklabel style = {font=\tiny},
xlabel = $t$,
ylabel = $f(t)+g(t)$,
ymin=-13,
ymax=13,
xtick={-13,13},
xticklabels={$-13$,$13$},
ytick={-13,13},
yticklabels={$-13$,$13$},
legend pos=outer north east,
legend style={cells={align=left}},
legend cell align={left},
clip=false
]
\addplot[very thick,red,smooth,samples=201,variable=t,domain=-13:13] {5*sin((2*t-pi/3) r)-8*cos((2*t+pi/6) r)};
\addlegendentry{\(5\sin(2t-\pi/3)-8\cos(2t+\pi/6)\)}
\addplot[blue,smooth,samples=201,variable=t,domain=-13:13] {13*sin((2*t+5.24) r)};
\addlegendentry{\(13\sin(2t+5.24)\)}
% Magnifying glass
\path (12.85,-6.75) coordinate (X);
\end{axis}
\spy [red] on (X) in node [right] at ([xshift=4mm]current axis.-20);
\end{tikzpicture}
\end{center}
\end{document}
旧答案：我认为主要问题是，在你看来，\plotbox你的ymin=-6.994,ymax=-7.006,意思是ymax<ymin，所以难怪情节是空的。这是一个非空的情节。
\documentclass{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}
\newsavebox\plotbox % To create a magnifying glass. From https://tex.stackexchange.com/a/267834/152550
\begin{lrbox}{\plotbox}
\begin{tikzpicture}[declare function={f(\t)=5*sin((2*\t-pi/3) r)-8*cos((2*\t+pi/6) r);
g(\t)=13*sin((2*\t+5.24) r);}]
\pgfmathsetmacro{\mymax}{g(12.806)-0.004}
\pgfmathsetmacro{\mymin}{f(12.802)+0.004}
\begin{axis} [
width=3.5cm,
height=3.5cm,
axis on top,
axis lines = center,
xticklabel style = {font=\tiny},
yticklabel style = {font=\tiny},
xlabel = $t$,
ylabel = $f(t)+g(t)$,
xtick={12.802,12.806},
xticklabels={$12.802$,$12.806$},
ytick={-7.006,-6.994},
yticklabels={$-7.006$,$-6.994$},
ymin=\mymin,
ymax=\mymax,
]
\addplot[very
thick,red,smooth,samples=201,variable=t,domain=12.802:12.806] {f(t)};
\addplot[blue,smooth,samples=201,variable=t,domain=12.802:12.806] {g(t)};
\end{axis}
\end{tikzpicture}%
\end{lrbox}
\begin{document}
\begin{center}
\begin{tikzpicture}
\begin{axis} [
axis on top,
axis lines = center,
axis equal image,
xticklabel style = {font=\tiny},
yticklabel style = {font=\tiny},
xlabel = $t$,
ylabel = $f(t)+g(t)$,
ymin=-13,
ymax=13,
xtick={-13,13},
xticklabels={$-13$,$13$},
ytick={-13,13},
yticklabels={$-13$,$13$},
legend pos=outer north east,
legend style={cells={align=left}},
legend cell align={left},
clip=false
]
\addplot[very thick,red,smooth,samples=201,variable=t,domain=-13:13] {5*sin((2*t-pi/3) r)-8*cos((2*t+pi/6) r)};
\addlegendentry{\(5\sin(2t-\pi/3)-8\cos(2t+\pi/6)\)}
\addplot[blue,smooth,samples=201,variable=t,domain=-13:13] {13*sin((2*t+5.24) r)};
\addlegendentry{\(13\sin(2t+5.24)\)}
% Magnifying glass
\coordinate (spyanchor) at (axis cs:12.804,-7);
\node[circle,draw,inner sep=0pt] at (axis cs:26,-2) (spyplot) {\usebox\plotbox};
\node[circle,draw,inner sep=5pt] at (spyanchor) (spynode) {};
\draw (spyplot) -- (spynode);
\end{axis}
\end{tikzpicture}
\end{center}
\end{document}
当然，您可以进一步调整这些值，直到您绝对满意为止。