![用方程式将线居中,同时分别标记每条线](https://linux22.com/image/352904/%E7%94%A8%E6%96%B9%E7%A8%8B%E5%BC%8F%E5%B0%86%E7%BA%BF%E5%B1%85%E4%B8%AD%EF%BC%8C%E5%90%8C%E6%97%B6%E5%88%86%E5%88%AB%E6%A0%87%E8%AE%B0%E6%AF%8F%E6%9D%A1%E7%BA%BF.png)
考虑以下 MWE
\documentclass[12pt,a4paper]
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\begin{document}
\begin{align}
\mathbb{P}(D_{1}\cap D_{2})=\mathbb{P}(D_{1})\mathbb{P}(D_{2}),\ \mathbb{P}(D_{2}\cap D_{3})=\mathbb{P}(D_{2})\mathbb{P}(D_{3}),\ \mathbb{P}(D_{1}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{3})\label{eq:equation}\\
(D_{1}\cap D_{2}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{2})\mathbb{P}(D_{3}\label{eq:moreequations}
\end{align}
当我显示此图时,方程式的顶行不在单个方程式的底行上居中。如何才能实现这一点,而不会丢失标签?
当我切换到不同的方法(例如使用array
来完成居中)时,我失去了分别标记所有线条的能力。
答案1
由于第一行太宽,我建议使用括号,以便清楚地表明数字指的是所有三种情况。
我建议使用个人命令,而不是重复\mathbb{P}
。
\documentclass[12pt,a4paper]{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\newcommand{\PP}{\mathbb{P}}
\begin{document}
\begin{gather}
\begin{cases}
\PP(D_{1}\cap D_{2})=\PP(D_{1})\PP(D_{2}), \\
\PP(D_{2}\cap D_{3})=\PP(D_{2})\PP(D_{3}), \\
\PP(D_{1}\cap D_{3})=\PP(D_{1})\PP(D_{3})
\end{cases}
\label{eq:equation}\\
\PP(D_{1}\cap D_{2}\cap D_{3})=\PP(D_{1})\PP(D_{2})\PP(D_{3})
\label{eq:moreequations}
\end{gather}
\end{document}
答案2
align
仅当需要指定对齐方式(使用&
)时才应该使用未对齐的方程式gather
,但这里第一行太宽(我猜,因为您没有给出页面宽度的指示)因此您可以使用split
(或更好的gathered
)将其分布在三行上,用一个数字。
\documentclass[12pt,a4paper]{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\begin{document}
\begin{gather}
\mathbb{P}(D_{1}\cap D_{2})=\mathbb{P}(D_{1})\mathbb{P}(D_{2}),
\ \mathbb{P}(D_{2}\cap D_{3})=\mathbb{P}(D_{2})\mathbb{P}(D_{3}),
\ \mathbb{P}(D_{1}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{3})\label{eq:equation}\\
(D_{1}\cap D_{2}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{2})\mathbb{P}(D_{3}
\label{eq:moreequations}
\end{gather}
so
\begin{gather}
\begin{gathered}\mathbb{P}(D_{1}\cap D_{2})=\mathbb{P}(D_{1})\mathbb{P}(D_{2})\\
\mathbb{P}(D_{2}\cap D_{3})=\mathbb{P}(D_{2})\mathbb{P}(D_{3})\\
\mathbb{P}(D_{1}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{3})
\end{gathered}\label{eq:equationb}\\
(D_{1}\cap D_{2}\cap D_{3})=\mathbb{P}(D_{1})\mathbb{P}(D_{2})\mathbb{P}(D_{3}
\label{eq:moreequationsb}
\end{gather}
\end{document}
答案3
我可以建议一下。
\documentclass[12pt,a4paper]{memoir}%your class was missing
\usepackage{amsmath,amsfonts,amssymb}
\usepackage[noabbrev]{cleveref}%for references, see below.
\DeclareMathOperator{\prob}{\mathbb{P}}% improves spacing and leads to a more consistent typography
\begin{document}
I would prefer the following layout, since it clearly shows what you refer to.
\begin{align}
\prob(D_{1}\cap D_{2})
&=\prob(D_{1})\prob(D_{2}),\label{eq:equation1}\\
\prob(D_{2}\cap D_{3})
&=\prob(D_{2})\prob(D_{3}),\label{eq:equation2}\\\
\prob(D_{1}\cap D_{3})
&=\prob(D_{1})\prob(D_{3}),\label{eq:equation3}\\
\prob(D_{1}\cap D_{2}\cap D_{3})
&=\prob(D_{1})\prob(D_{2})\prob(D_{3}).\label{eq:moreequations}
\end{align}
Use \cref{eq:equation1,eq:equation2,eq:equation3}, \crefrange{eq:equation1}{eq:equation3}, \cref{eq:moreequations} or \eqref{eq:moreequations} for references.
An alternative: For any $1\leq i<j\leq 3$, we have
\begin{align}
\prob(D_{i}\cap D_{j})
&=\prob(D_{i})\prob(D_{j}),\label{eq:equation}\\
\prob(D_{1}\cap D_{2}\cap D_{3}),
&=\prob(D_{1})\prob(D_{2})\prob(D_{3}).\label{eq:moreequations2}
\end{align}
Another alternative probably would be: The events $D_1, D_2,$ and $D_3$ are statistically independent.
\end{document}
您的代码中可能存在一些拼写错误。