添加等式中的标记

Question

我有一个阴谋，分数我想要自动计算分数（即，给定 x 坐标，我希望使用方程自动添加标记）。

\documentclass[12pt]{article}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{width = 7cm, compat = newest}

\begin{document}
    \begin{tikzpicture}
        \begin{axis}
            \addplot [no marks] {x^2};
            % Need to automate the following y-coordinate calculations
            \addplot [only marks] coordinates {(-2, {(-2)^2}) (0, {0^2}) (3, {3^2})};
        \end{axis}
    \end{tikzpicture}
\end{document}

Answer 1

使用samples at = {...}密钥：

\documentclass[border=3.141592mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{width = 7cm, compat = 1.17}

\begin{document}
    \begin{tikzpicture}
        \begin{axis}
            \addplot [no marks] {x^2};
            \addplot [only marks, samples at={-2,0,3}] {x^2};
        \end{axis}
    \end{tikzpicture}
\end{document}