如何使用 cnltx-example 編寫矩陣及其原始程式碼

Question

我想得到矩陣的輸出

\begin{pmatrix}
\frac{1}{2} & 0 & \frac{9}{5} \\
-2 & \frac{2}{3} & -\frac{1}{4} \\
12 & 0 & \frac{11}{7} \\
\end{pmatrix}

以及並排顯示的程式碼

\begin{example}[side-by-side]
\end{example} 

帶cnltx-example包。當我要編譯（使用amsart文檔類別）這個時，它給了一個錯誤。如何解決這個問題？

這是我的程式碼

\documentclass{amsart}
\usepackage{amsmath,amsthm,amssymb,amsxtra,amsopn}
\usepackage{cnltx-example}

\begin{document}

\begin{example}[side-by-side]
  Consider the following example.
  \[ (x + y)^2 = x^2 + 2xy + y^2\]
\end{example}

%The following gives an error at the time of compiling
\begin{example}[side-by-side]
  Consider the following matrix.
$\begin{pmatrix}
\frac{1}{2} & 0 & \frac{9}{5} \\
-2 & \frac{2}{3} & -\frac{1}{4} \\
12 & 0 & \frac{11}{7} \\
\end{pmatrix}$
\end{example}

\end{document}

Answer 1

顯然，cnltx-example需要將程式碼縮排兩個空格：

\documentclass{amsart}
\usepackage{amssymb}
\usepackage{cnltx-example}

\begin{document}

\begin{example}[side-by-side]
  Consider the following example.
  \[ (x + y)^2 = x^2 + 2xy + y^2\]
\end{example}

%The following gives an error at the time of compiling
\begin{example}[side-by-side]
  Consider the following matrix.
  $\begin{pmatrix} \frac{1}{2} & 0 & \frac{9}{5} \\
  -2 & \frac{2}{3} & -\frac{1}{4} \\
  12 & 0 & \frac{11}{7} \\
  \end{pmatrix}$
\end{example}

\end{document}