![标记抛物线上的一个点(如椭圆)](https://linux22.com/image/386350/%E6%A0%87%E8%AE%B0%E6%8A%9B%E7%89%A9%E7%BA%BF%E4%B8%8A%E7%9A%84%E4%B8%80%E4%B8%AA%E7%82%B9%EF%BC%88%E5%A6%82%E6%A4%AD%E5%9C%86%EF%BC%89.png)
我们可以使用以下方法在椭圆上标记一个点
\node[Maroon,draw,fill,circle,inner sep=1pt,label={-90:$X$}] (X)(-120:2cm 和 1cm){};
有没有办法定义抛物线上的一个点?
\documentclass[border=2pt]{standalone}
\usepackage[usenames,dvipsnames,svgnames]{xcolor}
\usepackage{tikz}
\color{Maroon}
\begin{document}
\begin{tikzpicture}
\draw[thin,gray!50](-3,-2) grid (3,2);
\draw[Maroon,thick] (0,0) ellipse (2cm and 1cm);
\node[Maroon,draw,fill,circle,inner sep=1pt,label={-90:$X$}] (X) at (-120:2cm and 1cm) {};
\draw[red] (-1,0) parabola[parabola height=1.5cm] (2,0);
\end{tikzpicture}
\end{document}
答案1
基于土拨鼠评论...
\documentclass[border=2pt]{standalone}
\usepackage[usenames,dvipsnames,svgnames]{xcolor}
\usepackage{tikz}
\usetikzlibrary{decorations.markings}
\color{Maroon}
\begin{document}
\begin{tikzpicture}
\draw[thin,gray!50](-3,-2) grid (3,2);
\draw[Maroon,thick] (0,0) ellipse (2cm and 1cm);
\node[Maroon,draw,fill,circle,inner sep=1pt,label={-90:$X$}] (X) at (-150:2cm and 1cm) {};
%\draw[red] (-1,0) parabola[parabola height=1.5cm] (2,0);
\draw[red,postaction={decorate,decoration={markings, mark=at position 0.5 with { \node[red,draw,fill,circle,inner sep=1pt,label={-90:$Y$}](Y){};}}}] (-1,0) parabola[parabola height=1.5cm] (2,0);
\end{tikzpicture}
\end{document}