%% %% Der Mathematiksatz mit LaTeX, 1. Auflage 2009 %% %% Example 6-11-9 on page 115. %% %% Copyright (C) 2009 Herbert Voss %% %% It may be distributed and/or modified under the conditions %% of the LaTeX Project Public License, either version 1.3 %% of this license or (at your option) any later version. %% %% See http://www.latex-project.org/lppl.txt for details. %% \documentclass[]{ttctexa} \pagestyle{empty} \setcounter{page}{6} \setlength\textwidth{355.65944pt} \AtBeginDocument{\setlength\parindent{0pt}} \setcounter{equation}{59} \renewcommand\theequation{6.\arabic{equation}} \StartShownPreambleCommands \usepackage{amsmath} \newcounter{mySubCounter} \newcommand{\twocoleqn}[2]{% \setcounter{mySubCounter}{0}\let\OldTheEquation\theequation% \renewcommand\theequation{\OldTheEquation\alph{mySubCounter}}% \noindent\begin{minipage}{.49\textwidth} \begin{align}\refstepcounter{mySubCounter}#1\end{align} \end{minipage}\hfill\addtocounter{equation}{-1}% \begin{minipage}{.49\textwidth} \begin{align}\refstepcounter{mySubCounter}#2\end{align} \end{minipage}\let\theequation\OldTheEquation} \StopShownPreambleCommands \begin{document} \twocoleqn{y=f(x)}{y=f(z)} \begin{align} z &= f(x,y) \end{align} \end{document}