逐项对齐

Question

我怎样才能实现方程式与first thing和在同一行开始second thing？

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}

\usepackage{mathbbol}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}

\begin{document}
\begin{itemize}
\item first thing:
      \begin{align*}
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{align*}
\item secong thing: 
      \begin{align*}
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{align*}
\end{itemize}
\end{document}

Answer 1

您可能需要这个小小的改进：使用该eqparbox包，您可以让所有项目的方程式从同一点开始。

无关： 自 3.10 版本以来，的语言选项babel应该与文档类一起加载，以确保所有语言相关文件都知道主文档语言。

\documentclass[a4paper,10pt, english]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{amsmath}

\usepackage{eqparbox}


\begin{document}

\begin{itemize}
\item \eqmakebox[things][l]{first thing: }
     $ \begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned} $
\item \eqmakebox[things][l]{second thing: }
     $ \begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned} $
\end{itemize}

\end{document} 

Answer 2

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}

\usepackage{mathbbol}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}

\begin{document}
\begin{itemize}
\item $\displaystyle\begin{aligned}[t]
      \text{first thing: } c^2&=a^2+b^2\\
                           c^2&=a^2+b^2
      \end{aligned}$
\item $\displaystyle\begin{aligned}[t]
      \text{secong thing: } c^2&=a^2+b^2\\
                            c^2&=a^2+b^2
      \end{aligned}$
\end{itemize}
\end{document}

Answer 3

像这样？

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}

\usepackage{mathbbol}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}

\begin{document}
\begin{itemize}
\item first thing: $
      \begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned}$
\item secong thing: $
      \begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned}$
\end{itemize}
\end{document}

Answer 4

以下示例使用aligned内联数学环境而不是未编号的显示环境align*：

\documentclass[a4paper,10pt]{article}
\usepackage{amsmath}

\begin{document}
\begin{itemize}
\item First thing:\\[.5ex]
      $\displaystyle\begin{aligned}
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2,
      \end{aligned}$\\
      where $c$ is real.
\item Second thing:\\[.5ex]
      $\displaystyle\begin{aligned}
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2\text{, where $c$ is real.}
      \end{aligned}$
\end{itemize}
\end{document}

或者，如果第一个方程式应该在文本行中，则可选参数[t]会有所帮助：

\documentclass[a4paper,10pt]{article}
\usepackage{amsmath}

\begin{document}
\begin{itemize}
\item First thing:
      $\begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned}$
\item Second thing:
      $\begin{aligned}[t]
      c^2&=a^2+b^2\\
      c^2&=a^2+b^2
      \end{aligned}$
\end{itemize}
\end{document}