如何使用乳胶绘制此图

Question

我想使用 tikz 绘制此图表，你能帮我吗？

Answer 1

我根本不擅长 tikz，但作为起点，我建议您使用这个例子：

\documentclass[tikz]{standalone}

\begin{document}
\begin{tikzpicture}
 
\draw[ultra thick, black] (-0.3,3.7) .. controls (2.3,0.1) and (3.1,3.9) .. (5.1,4) .. controls (6.5,4.1) and (6.5,3) .. (8.2,2)node[black, above=15pt,pos=.9]{$f(x)$};

\draw[ultra thick, black] (-0.3,2.7) .. controls (2.3,-0.9) and (3.1,2.9) .. (5.1,3) .. controls (6.5,3.1) and (6.5,2) .. (8.2,1)node[black, below=15pt,pos=.7]{$f(x)$};

\filldraw[black] (0.6,2.7) circle (2pt) node[anchor=south] {$a_i^R$};

\draw[thick, red, dashed] (1.6,0)--(1.6,5);
\draw[thick, red, dashed] (5.2,0)--(5.2,5);
\draw [thick, ->] (-.5,2.7)--(8.3,2.7) node[below]{$y$};
\end{tikzpicture}
\end{document}