我想用 Tikz 绘制一个函数。我是这样做的：
\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[german]{babel}
\usepackage{mathtools}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{calc}
\pgfplotsset{compat=1.11}
\begin{document}
\begin{figure}
\begin{tikzpicture}[scale=10]
\draw (0,0) -- coordinate (x axis mid) (1,0);
\draw (0,0) -- coordinate (y axis mid) (0,0.59);
\foreach \x in {0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1}
\draw (\x,0.1pt) -- (\x,-0.3pt)
node[anchor=north] {\x};
\foreach \x in {0.05,0.15,0.25,0.35,0.45,0.55,0.65,0.75,0.85,0.95}
\draw (\x,0.07pt) -- (\x,-0.2pt)
node[anchor=north] {};
\foreach \y in {0.0,0.1,0.2,0.3,0.4,0.5}
\draw (0.1pt,\y) -- (-0.3pt,\y)
node[anchor=east] {\y};
\foreach \y in {0.05,0.15,0.25,0.35,0.45,0.55}
\draw (0.07pt,\y) -- (-0.2pt,\y)
node[anchor=east] {};
\addplot [] {$\frac{1+ \frac{x}{1-x}}{\sqrt{2*\pi}*\sqrt{{\frac{x}{1-x}}^{2} + 1}}$};
\draw [-] (0,0.4) -- (1,0.4);
\end{tikzpicture}
\end{figure}
\end{document}
不幸的是，LaTeX 无法编译，并指出这
\addplot [] {$\frac{1+ \frac{x}{1-x}}{\sqrt{2*\pi}*\sqrt{{\frac{x}{1-x}}^{2} + 1}}$};
是一个未定义的控制序列。您知道如何绘制此函数吗？
非常感谢！并致以最诚挚的问候！
答案1
我建议您实际使用 PGFPlots，因为您已经将其包括在内。您是否正在尝试做这样的事情？
\documentclass[tikz]{standalone}
\usepackage{pgfplots}
%why are you not using at least compat=1.3?
\pgfplotsset{compat=1.11}
\begin{document}
\begin{tikzpicture}[scale=10]
\begin{axis}[
xmin=0,
xmax=1,
ymin=0,
ymax=0.6,
xtick={0,0.1,...,1.1},
minor xtick={0.05,0.15,...,0.95},
ytick={0,0.1,...,0.6},
minor ytick={0.05,0.15,...,0.55},
]
\addplot[domain=0:1,samples=50] {(1+(x/(1-x)))/(sqrt(2*pi)*sqrt((x/(1-x))^2 +1))};
\addplot[] plot coordinates{(0,0.4) (1,0.4)};
\end{axis}
\end{tikzpicture}
\end{document}
由此产生了如下结果：
如果需要的话，可以轻松更改刻度等。