![画一个圆圈-LaTeX代码](https://linux22.com/image/339667/%E7%94%BB%E4%B8%80%E4%B8%AA%E5%9C%86%E5%9C%88-LaTeX%E4%BB%A3%E7%A0%81.png)
答案1
以下示例使用点/角度的均匀分布。
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\def\Radius{20mm}
\draw
(0, 0) coordinate (M) circle[radius=\Radius]
;
% Full circle evenly divided into 14 pieces
\filldraw[fill=white, radius=2pt]
\foreach \i in {0, ..., 3, 12, 13} {
(M) +(90 - \i * 360/14:\Radius) circle[]
}
;
\path
\foreach \i/\a in {0/1, 1/2, 2/3, 3/4, 12/20, 13/21} {
(M) -- node[pos=.8] {$a_{\a}$} +(90 - \i * 360/14:\Radius)
}
;
\fill[radius=1.5pt]
\foreach \i in {4, ..., 11} {
(M) +(90 - \i * 360/14:.8*\Radius) circle[]
}
;
\end{tikzpicture}
\end{document}