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在数组中添加方程编号

tag-icon • tag-icon equations numbering arrays
在数组中添加方程编号

我正在努力对齐我的方程式并为它们提供一个数字。我在谷歌上搜索，但没有找到数组环境的解决方案。我尝试了 env align。但只使用arrayenv。我设法得到了我想要的结果。现在我想在行末标记两个对话方程式（最好垂直居中）。

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{amsmath}
\usepackage{amssymb,amsthm}
\begin{document}
\begin{equation}
\begin{array}{lrcl}
\textbf{Conservation of energy}     & E_{kin}               &=& E'_{kin}                \\
                & m_1 v_1^2 + m_2 v_2^2         &=& m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \\
                & m_1 (v_1^2 - {v'}_1^2)        &=& m_2 ({v'}_2^2 - v_2^2)      \\
                & m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)     &=& m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)   \\
\\

\textbf{Conservation of momentum}   & p                 &=& p' \\
                & m_1 v_1 + m_2 v_2             &=& m_1 {v'}_1 + m_2 {v'}_2\\
                & m_1 (v_1 - {v'}_1)            &=& m_2 ({v'}_2 - v_2)\\
\end{array}
\end{equation}
\end{document}

为了更清楚起见：我希望黑色数字消失并出现红色数字：

添加数字的屏幕截图

答案1

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amsmath 有几种环境用于对每行进行编号，或者像这里一样对整个组进行编号。不要将array此类显示结构用于此类显示结构，因为间距和样式不是为此设计的。

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{amsmath}
\usepackage{amssymb,amsthm}
\begin{document}

\textbf{Conservation of energy}
\begin{equation}
\begin{split}
  E_{\mathrm{kin}}                  &= E'_{\mathrm{kin}}                   \\
  m_1 v_1^2 + m_2 v_2^2             &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \\
  m_1 (v_1^2 - {v'}_1^2)            &= m_2 ({v'}_2^2 - v_2^2)              \\
  m_1 (v_1 + {v'}_1) (v_1 - {v'}_1) &= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2) 
\end{split}
\end{equation}

\textbf{Conservation of momentum}  
\begin{equation}
\begin{split}
  p                  &= p'                      \\
  m_1 v_1 + m_2 v_2  &= m_1 {v'}_1 + m_2 {v'}_2 \\
  m_1 (v_1 - {v'}_1) &= m_2 ({v'}_2 - v_2)
\end{split}
\end{equation}


\end{document}

答案2

你可以这样做：

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{amsmath}
\usepackage{amssymb,amsthm}
\begin{document}
\begin{align}
  & \textbf{Conservation of energy} 
   & E_{kin}                          &= E'_{kin}                         \notag\\
  && m_1 v_1^2 + m_2 v_2^2            &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2}    \\
  && m_1 (v_1^2 - {v'}_1^2)           &= m_2 ({v'}_2^2 - v_2^2)           \notag\\
  && m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)&= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)\notag\\[2ex]
  & \textbf{Conservation of momentum}
   & p                                &= p'                               \notag\\
  && m_1 v_1 + m_2 v_2                &= m_1 {v'}_1 + m_2 {v'}_2                \\
  && m_1 (v_1 - {v'}_1)               &= m_2 ({v'}_2 - v_2)               \notag
\end{align}
\end{document}

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答案3

您可以使用alignedat，但需要一些手动工作来在两个部分之间共享列宽；我们在全局对齐中确定最宽的列并在进行显示之前设置三个尺寸。

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{amsmath,mathtools,amssymb,amsthm}

\usepackage{lipsum} % just for the example

\newlength{\izA}\newlength{\izB}\newlength{\izC}
\newcommand{\mmb}[3]{\mathmakebox[#1][#2]{\displaystyle#3}}

\begin{document}

\lipsum*[2]
%%% settings for the display
\settowidth{\izA}{\textbf{Conservation of momentum}}%
\settowidth{\izB}{$\displaystyle m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)$}%
\settowidth{\izC}{$\displaystyle m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)$}%
%%%
\begin{gather}
\begin{alignedat}{2}
&\mmb{\izA}{l}{\textbf{Conservation of energy}}
   & \mmb{\izB}{r}{E_{\mathrm{kin}}}   &= \mmb{\izC}{l}{E'_{\mathrm{kin}}}    \\
  && m_1 v_1^2 + m_2 v_2^2             &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \\
  && m_1 (v_1^2 - {v'}_1^2)            &= m_2 ({v'}_2^2 - v_2^2)              \\
  && m_1 (v_1 + {v'}_1) (v_1 - {v'}_1) &= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)
\end{alignedat}
\\
\begin{alignedat}{2}
&\textbf{Conservation of momentum}
   & \mmb{\izB}{r}{p}                  &= \mmb{\izC}{l}{p'}                   \\
  && m_1 v_1 + m_2 v_2                 &= m_1 {v'}_1 + m_2 {v'}_2             \\
  && m_1 (v_1 - {v'}_1)                &= m_2 ({v'}_2 - v_2)
\end{alignedat}
\end{gather}
\lipsum[3]

\end{document}

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替代解决方案是split，因此我们需要更少的测量。

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{amsmath,mathtools,amssymb,amsthm}

\usepackage{lipsum} % just for the example

\newlength{\lefthandside}
\newcommand{\leftbox}[2][]{%
  \makebox[\lefthandside][s]{#1\hfill$\displaystyle#2$}%
}

\begin{document}

\lipsum*[2]
%%% settings for the display
\settowidth{\lefthandside}{%
  \textbf{Conservation of momentum}%
  \quad
  $\displaystyle m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)$%
}%
%%%
\begin{align}
\begin{split}
\leftbox[\textbf{Conservation of energy}]
  {E_{\mathrm{kin}}}                        &= E'_{\mathrm{kin}} \\
\leftbox{m_1 v_1^2 + m_2 v_2^2}             &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \\
\leftbox{m_1 (v_1^2 - {v'}_1^2)}            &= m_2 ({v'}_2^2 - v_2^2)              \\
\leftbox{m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)} &= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)
\end{split}
\\
\begin{split}
\leftbox[\textbf{Conservation of momentum}]
  {p}                                       &= p'                   \\
\leftbox{m_1 v_1 + m_2 v_2}                 &= m_1 {v'}_1 + m_2 {v'}_2             \\
\leftbox{m_1 (v_1 - {v'}_1)}                &= m_2 ({v'}_2 - v_2)
\end{split}
\end{align}
\lipsum[3]

\end{document}

在此处输入图片描述

答案4

如果您希望标题与左边距对齐，这里有两个解决方案，基于命令\shortintertext和mathtools环境flalign。每个解决方案都有两种变体，具体取决于符号组是否=对齐。这些变体在方程编号的位置也有所不同：

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{mathtools}
\usepackage{amssymb,amsthm}
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.2pt}

\begin{document}

\begin{align}
  \shortintertext{\bfseries Conservation of energy}
  E_\mathrm{kin}    & = E'_\mathrm{kin}                         \notag \\
  m_1 v_1^2 + m_2 v_2^2       & = m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2}            \\
  m_1 (v_1^2 - {v'}_1^2)       & = m_2 ({v'}_2^2 - v_2^2)           \notag        \\
  m_1 (v_1 + {v'}_1) (v_1 - {v'}_1) & = m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)\notag        \\[2ex]
  \shortintertext{\bfseries Conservation of momentum}
  p     & = p'                               \notag        \\
  m_1 v_1 + m_2 v_2     & = m_1 {v'}_1 + m_2 {v'}_2                        \\
  m_1 (v_1 - {v'}_1)      & = m_2 ({v'}_2 - v_2)               \notag
\end{align}
\vspace{1cm}
\begin{flalign}
  & \textbf{Conservation \rlap{of energy}}
  & E_\mathrm{kin}      &= E'_\mathrm{kin}             &  &              \notag\\
  && m_1 v_1^2 + m_2 v_2^2     &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \raisetag{1cm}   \\
  && m_1 (v_1^2 - {v'}_1^2)      &= m_2 ({v'}_2^2 - v_2^2)           \notag\\
  && m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)&= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)\notag\\[2ex]
  & \textbf{Conservation \rlap{of momentum}}
  & p   &= p'                               \notag\\
  && m_1 v_1 + m_2 v_2  &= m_1 {v'}_1 + m_2 {v'}_2                \\
  && m_1 (v_1 - {v'}_1)  &= m_2 ({v'}_2 - v_2)               \notag
\end{flalign}
\newpage
\begin{gather}
  \shortintertext{\bfseries Conservation of energy}
  \begin{aligned}
    E_\mathrm{kin}  & = E'_\mathrm{kin}                     \\
    m_1 v_1^2 + m_2 v_2^2     & = m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2} \\
    m_1 (v_1^2 - {v'}_1^2)      & = m_2 ({v'}_2^2 - v_2^2)              \\
    m_1 (v_1 + {v'}_1) (v_1 - {v'}_1) & = m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)
  \end{aligned}\\[2ex]
  \shortintertext{\bfseries Conservation of momentum}
  \begin{aligned}
    p   & = p'                      \\
    m_1 v_1 + m_2 v_2  & = m_1 {v'}_1 + m_2 {v'}_2 \\
    m_1 (v_1 - {v'}_1) & = m_2 ({v'}_2 - v_2)
  \end{aligned}
\end{gather}
\vspace{1cm}

\begin{flalign}
  & \textbf{Conservation of energy }
  &  & \begin{aligned}[t]
  E_\mathrm{kin}    &= E'_\mathrm{kin}                \\
  m_1 v_1^2 + m_2 v_2^2      &= m_1 {v'}_{1}^{2} + m_2 {v'}_{2}^{2}    \\
  m_1 (v_1^2 - {v'}_1^2)     &= m_2 ({v'}_2^2 - v_2^2)    \\
  m_1 (v_1 + {v'}_1) (v_1 - {v'}_1)&= m_2 ({v'}_2 + v_2) ({v'}_2 - v_2)
  \end{aligned}
  &  &
  \\[2ex]
  & \textbf{Conservation of  momentum}
  & &  \begin{aligned}[t]
  p     &= p'          \\
  m_1 v_1 + m_2 v_2   &= m_1 {v'}_1 + m_2 {v'}_2                \\
  m_1 (v_1 - {v'}_1)   &= m_2 ({v'}_2 - v_2)
  \end{aligned}
  &  &
\end{flalign}

\end{document}

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