如何为定理的背景着色

Question

如何在 LaTeX 中像下图一样给背景上色

Answer 1

这很容易tcolorbox

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage[many]{tcolorbox}

\newtheorem{theorem}{Theorem}[section]
\tcolorboxenvironment{theorem}{
  colback=blue!5!white,
  boxrule=0pt,
  boxsep=1pt,
  left=2pt,right=2pt,top=2pt,bottom=2pt,
  oversize=2pt,
  sharp corners,
  before skip=\topsep,
  after skip=\topsep,
}

\begin{document}

\section{Title}

Some text

\begin{theorem}
If $f$ is integrable on $[a,b]$, then it holds that
\[
\lim_{n\to\infty}\frac{b-a}{n}\sum_{k=1}^n f\Bigl(a+k\cdot\frac{b-a}{n}\Bigr)
=\int_a^b f(x)\,dx
\]
\end{theorem}

\begin{theorem}[Again]
If $f$ is integrable on $[a,b]$, then it holds that
\[
\lim_{n\to\infty}\frac{b-a}{n}\sum_{k=1}^n f\Bigl(a+k\cdot\frac{b-a}{n}\Bigr)
=\int_a^b f(x)\,dx
\]
\end{theorem}

\end{document}

请注意，您仍然可以使用可选参数。

Answer 2

这个怎么样？每个细节都以内联方式描述。

\documentclass{article}
\usepackage{amsthm,tcolorbox,xcolor,lipsum}   % lipsum only needed for some blindtext.
\newtheorem{mytheorem}{Theorem}[section]      % Create new theorem called 'Theorem'.
\newenvironment{mycolortheorem}[1][]{%        % Create new environment which wraps our Theorem into a tcolorbox.
   \begin{tcolorbox}[colback=blue!5!white,%     Background color.
      width=\dimexpr\linewidth+10pt\relax,%     Allow your box to be bigger than \linewidth ...
      enlarge left by=-5pt,%                    ... in order to have the text properly aligned. ...
      enlarge right by=-5pt,%                   ... Note that boxsep = -enlargeLeft = -enlargeRight = 0.5*enlargement of width. ...
      boxsep=5pt,%                              ... This is necessary to keep everything good looking.
      left=0pt,%                                Avoid extra space on the left, ...
      right=0pt,%                               ... right, ...
      top=0pt,%                                 ... top, ...
      bottom=0pt,%                              ... and bottom.
      arc=0pt,%                                 Corners not rounded.
      boxrule=0pt,%                             No boxrule.
      colframe=white]{}{}%                      Make rest of the boxrule invisible.
      \ifstrempty{#1}{%                         If you didn't specify the optional argument of Theorem ...
         \begin{mytheorem}%                     ... then open a normal Theorem ...
      }{%                                       ... else ...
         \begin{mytheorem}[#1]%                 ... open a Theorem and use the optional argument.
      }%
}{%
      \end{mytheorem}%                          Close every environment.
   \end{tcolorbox}%
}

\begin{document}
   \lipsum[1]
   \begin{mycolortheorem}[named Theorem]
      \lipsum[2]
   \end{mycolortheorem}
   \begin{mycolortheorem}
      unnamed theorem.
      \begin{equation}
         1+1=2
      \end{equation}
   \end{mycolortheorem}
   \lipsum[3]
   
\end{document}

Answer 3

我认为您可以使用框架包。

\documentclass{article}
\usepackage{framed}
\usepackage{xcolor}
\usepackage{lipsum}
\begin{document}
\colorlet{shadecolor}{gray!10}
\begin{shaded}
\noindent\textbf{Theorem 1.} \lipsum[3]
\end{shaded}
\end{document}