如何用TikZ图片绘制两个函数

Question

我想画下面的图但我不知道该怎么画。

这是我的代码，尽管它没有运行：

‎‎\begin{tikzpicture}‎[>=stealth,scale=10]‎
\draw[color=gray!30,very thin](-0.1,-0.004)‎
gri‎d[ystep=0.01,xstep=0.1](1.02,0.042);‎
\draw[->](-0.1,0)--(1.02,0);‎
\draw[->](0,-0.004)--(0,0.042);‎‎‎
\draw[thick,blue,domain=0:1.02,samples=200] plot(\x,{(\x)/(70*(2-\x*\x))}) node[below‎] {‎$y=‎\frac{q}{70(2-‎q^2)}‎‎‎$‎};;‎‎‎‎
\draw[thick,red,domain=0:1,samples=200] plot(\x,{(1+sqrt(1-\x*\x))/(70)}) node[above] {‎$y=‎\frac{1}{70}(1+\sqrt{1-‎q^2})‎‎‎$‎};;‎‎‎
\end{tikzpicture}

有人知道我该如何改变我的代码来绘制这个吗？

Answer 1

编辑： 抱歉，在第一个版本的答案中，我重写了您的方程式，但出现了错误。现在已更正。

以下是绘制图表的两个版本：

• 与传说
• 标签位于曲线上方/下方

\documentclass[margin=3mm, preview]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}
    \begin{tikzpicture}
\begin{axis}[height=44mm, width=88mm,
    grid=both,
    minor tick num=4,
    minor grid style = {very thin},
    ymax = 0.03, 
    xlabel = $x$,   ylabel = $y$,
    scaled y ticks=false,
    yticklabel style={/pgf/number format/.cd, fixed,  precision=2},
    tick label style = {font=\footnotesize},
    enlarge x limits = false,
    domain = 0:1,   samples = 201, no marks,
every axis plot post/.append style={very thick},
    legend style={cells={anchor=west, yshift=3mm}, 
                  font=\scriptsize,
                  legend pos = outer north east}
            ]
\addplot    {x/(70*(2-x^2))};
\addplot    {(1+sqrt(1-x^2))/70};
    \legend{$\frac{x}{70(2-x^2)}$, $\frac{1}{70(1+\sqrt{1-x^2})}$}
\end{axis}
    \end{tikzpicture}
    
\bigskip
    \begin{tikzpicture}[
N/.style = {font= \footnotesize, text=black, pos=0.6}
                            ]
\begin{axis}[height=44mm, width=88mm,
    grid=both,
    minor tick num=4,
    minor grid style = {very thin},
    ymax = 0.03,
    xlabel = $x$,   ylabel = $y$,
    scaled y ticks=false,
    yticklabel style={/pgf/number format/.cd, fixed,  precision=2},
    tick label style = {font=\footnotesize},
    enlarge x limits = false,
    domain = 0:1,   samples = 201, no marks,
every axis plot post/.append style={very thick},
            ]
\addplot    {x/(70*(2-x^2))}        node[N, above] {$\frac{x}{70(2-x^2)}$};
\addplot    {(1+sqrt(1-x^2))/70}    node[N, below] {$\frac{1}{70(1+\sqrt{1-x^2})}$};
\end{axis}
    \end{tikzpicture}
\end{document}