Fitting unbreakable large equation on one line in a twocolumn layout

Question

I have an equation in my document which is unbreakable and does not fit on one line using the twocolumn global option. Am I forced to shrink the text size here? And how do I go about doing it? \resizebox does not function in math mode.

\documentclass[twocolumn]{ltxdoc}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\sum_{q_\mathrm{total}=0}^{q_A+N_A+q_B+N_B-2}\left(\sum_{q_A=0}^{q_\mathrm{total}}\left(\binom{q_A+N_A-1}{q_A}\binom{q_B+N_B-1}{q_B}\right)\right)x^{q_\mathrm{total}}
\end{equation}
\end{document}

Answer 1

Resizebox should work.

\documentclass[twocolumn]{ltxdoc}
\usepackage{amsmath}
\usepackage{lipsum}
\usepackage{graphics}
\begin{document}
\lipsum[1]
\begin{equation}
\resizebox{0.5\textwidth}{!}{$\sum_{q_\mathrm{total}=0}^{q_A+N_A+q_B+N_B-2}\left(\sum_{q_A=0}^{q_\mathrm{total}}\left(\binom{q_A+N_A-1}{q_A}\binom{q_B+N_B-1}{q_B}\right)\right)x^{q_\mathrm{total}}$}
\end{equation}
\lipsum[2-4]
\end{document}

Or maybe consider splitting your equation.

Answer 2

The cuted package (from the sttools bundle) can temporarily leave two columns mode with its strip environment. An example with the equation entered in the second column:

\documentclass[twocolumn]{ltxdoc}
\usepackage{mathtools, cuted}
\usepackage{lipsum, color}

\begin{document}
\lipsum[1-2]

\lipsum[1]

\textsf{\color{red}Equation entered here: }

\begin{strip}
\begin{equation}
  \sum_{q_\mathrm{total}=0}^{q_A+N_A+q_B+N_B-2}\left(\sum_{q_A=0}^{q_\mathrm{total}}\left(\binom{q_A+N_A-1}{q_A}\binom{q_B+N_B-1}{q_B}\right)\right)x^{q_\mathrm{total}}
\end{equation}
\end{strip}

Text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text.

\lipsum[3-5]
\end{document} 

Answer 3

I don't think you have a much better option than this. Btw, you seem to use q_A for two different things.

\documentclass[twocolumn]{ltxdoc}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\sum_{q_\mathrm{tot}=0}^{Q_A+Q_B-2}\sum_{q_A=0}^{q_\mathrm{tot}}{\textstyle\binom{Q_A-1}{q_A}\binom{Q_B-1}{q_B}}x^{q_\mathrm{tot}},
\end{equation}
where $Q_A=q_A+N_A$ and $Q_B=q_B+N_B$.
\end{document}