\begin{flalign}
x &= 4^2 - 1\\
&= 16 - 1\\
&= 15&
\end{flalign}
上述代码将导致(1)
的右侧出现x = 4^2 - 1
,每一行都是如此。
我想在 旁边放上普通的单词(1), (2), etc.
。
假设是这样的:
\begin{flalign}
x &= 4^2 - 1 \someFunction{given}\\
&= 16 - 1 \someFunction{exponent}\\
&= 15 \someFunction{substraction}&
\end{flalign}
答案1
flalign
由于以下原因,我永远不会使用;请自行选择。
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\section{Bad example with \texttt{flalign}}
This is bad because the tags are too far away from the equations
\begin{flalign}
&& x &= 4^{2} - 1 && \text{given}\\
&& &= 16 - 1 && \text{exponent}\\
&& &= 15 && \text{subtraction}
\end{flalign}
\section{Better example with \texttt{align}}
This is better because the tags are not mingled with the
equation number
\begin{align}
x &= 4^{2} - 1 && \text{given}\\
&= 16 - 1 && \text{exponent}\\
&= 15 && \text{subtraction}
\end{align}
\section{Even better example with \texttt{alignat}}
Here we set the tags nearer to the equations, which is
where they belong
\begin{alignat}{2}
x &= 4^{2} - 1 && \qquad\text{(given)}\\
&= 16 - 1 && \qquad\text{(exponent)}\\
&= 15 && \qquad\text{(subtraction)}
\end{alignat}
\end{document}
答案2
这里有两种变体:第一种将考虑文本宽度的方程式中心组放置在方程式编号旁边;第二种将文本放在零宽度的框中,看起来更像是一个对齐环境,没有文本:
\documentclass[12pt,a4paper,twoside]{article}
\usepackage[utf8]{inputenc}
\usepackage[showframe, nomarginpar]{geometry}
\usepackage{amsmath}
\begin{document}
\begin{flalign}
& & x &= 4^2 - 1 & \text{given}\\
& & &= 16 - 1 & \text{exponent}\\
& & &= 15 & \text{substraction}
\end{flalign}
\begin{flalign}
& & x &= 4^2 - 1 & \llap{given}\\
& & &= 16 - 1 & \llap{exponent}\\
& & &= 15 & \llap{substraction}
\end{flalign}
\begin{align}
x &= 4^2 - 1 \\
&= 16 - 1 \\
&= 15
\end{align}
\end{document}