我尝试绘制以下函数;但是,它们在 x=[-5,5] 处被截断,我不知道为什么。任何帮助都将不胜感激。
\documentclass{article}
\usepackage{pgfplots}
\usepgfplotslibrary{external}
\tikzexternalize[shell escape=-enable-write18] %needed for the MiKTeX compiler
\tikzset{external/force remake}
\begin{document}
\begin{tikzpicture}
\begin{axis}[xmin=-10,xmax=10]
\addplot [mark=none, smooth, color=blue]{x^2+2};
\addplot [mark=none, smooth, color=red]{x^2};
\addplot [mark=none, smooth, color=green]{x^2-2};
\addlegendentry{$x^2+2$}
\addlegendentry{$x^2$}
\addlegendentry{$x^2-2$}
\end{axis}
\end{tikzpicture}
\begin{tikzpicture}
\begin{axis}[xmin=-10,xmax=10]
\addplot [mark=none, smooth, color=blue]{(x+2)^2};
\addplot [mark=none, smooth, color=red]{x^2};
\addplot [mark=none, smooth, color=green]{(x-2)^2};
\addlegendentry{$(x+2)^2$}
\addlegendentry{$x^2$}
\addlegendentry{$(x-2)^2$}
\end{axis}
\end{tikzpicture}
\end{document}
答案1
您需要告诉每个\addplot
要绘制的域,即
\addplot [mark=none, smooth, color=blue, domain=-10:10]{x^2+2};
正如 Knabber 所指出的,一种快捷方式是将域边界放在轴选项中,即
\begin{axis}[xmin=-10,xmax=10, domain=-10:10]
\addplot [mark=none, smooth, color=blue]{x^2+2};
\addplot [mark=none, smooth, color=red]{x^2};
\addplot [mark=none, smooth, color=green]{x^2-2};
...
\end{axis}
最后,如果你不喜欢重复,你可以这样做
\begin{axis}[enlargelimits=false, domain=-10:10]
其中,enlargelimits=false
轴边界紧贴域(无填充)。