[Tex/LaTex] How to insert white vertical space between subequations

spacingsubequations

I have the following MWE

\documentclass[11pt]{article}
\usepackage{empheq}

\newcommand*\widefbox[1]{\fbox{\hspace{2em}#1\hspace{2em}}}

\begin{document}
\begin{subequations}
\begin{empheq}[box=\widefbox]{align}
  a & = b \\
  c & = d
\end{empheq}
\end{subequations}
\end{document}

and I'd like to insert some variable-size vertical white space between the subequations to make them look nicer in the box. How may I do this?

Best Answer

\documentclass[11pt]{article}
\usepackage{empheq}

\newcommand*\widefbox[1]{\fbox{\hspace{2em}#1\hspace{2em}}}

\begin{document}
\begin{subequations}
\begin{empheq}[box=\widefbox]{align}
  a & = b \\[2in]
  c & = d
\end{empheq}
\end{subequations}
\end{document}
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