Too long equation without splitting

Question

I am writing an equaition which is too long-wide. I don't want it to split. I tried to change the fontsize within the equation enviroment but it didn't work. I am using

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsthm}
\begin{document}
\begin{equation}
{\footnotesize G=centroid\cdot \frac{range[V]}{\#\,channels}\cdot\frac{W_{pair}[eV]}    {E_{particle}[keV]}\cdot \frac{1}{(coarse\,gain)\cdot(fine\,gain)}\cdot \frac{10^6}   {X[mV]\cdot E_{cg}[eV]}}
\label{eq:Gain}
\end{equation}
\end{document}

Is there a way to achieve that? My output is

Any ideas?

Answer 1

You could set the fractions in \textstyle:

\documentclass[11pt]{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\begin{document}
\begin{equation}
  G=\textstyle\text{centroid}\cdot \frac{\text{range}[V]}{\text{\# channels}}\cdot
    \frac{W_{\text{pair}}[eV]}{E_{\text{particle}}[keV]}\cdot 
    \frac{1}{(\text{coarse gain})\cdot(\text{fine gain})}\cdot 
    \frac{10^6}{X[mV]\cdot E_{cg}[eV]}
\label{eq:Gain}
\end{equation}
\end{document}

(you may even consider using \small centroid as well) or scale it to fix using \resizebox from graphicx:

\documentclass[11pt]{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\usepackage{graphicx}% http://ctan.org/pkg/graphicx
\begin{document}
\begin{equation}
  \resizebox{.9\textwidth}{!}{$\displaystyle
    G=\text{centroid}\cdot \frac{\text{range}[V]}{\text{\# channels}}\cdot
    \frac{W_{\text{pair}}[eV]}{E_{\text{particle}}[keV]}\cdot 
    \frac{1}{(\text{coarse gain})\cdot(\text{fine gain})}\cdot 
    \frac{10^6}{X[mV]\cdot E_{cg}[eV]}$}
\label{eq:Gain}
\end{equation}
\end{document}

Answer 2

Package resizegather allows the automatically resizing the equation to line width, if the equation is too large:

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{resizegather}
\begin{document}
\begin{gather}
G=centroid\cdot
\frac{range[V]}{\#\,channels}\cdot\frac{W_{pair}[eV]}
{E_{particle}[keV]}\cdot \frac{1}{(coarse\,gain)\cdot(fine\,gain)}\cdot
\frac{10^6}   {X[mV]\cdot E_{cg}[eV]}
\label{eq:Gain}
\end{gather}
\end{document}

And with setting text and units as text and not as product of variables:

\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{resizegather}
\begin{document}
\begin{gather}
G=\text{centroid}\cdot
\frac{\text{range}[\text{V}]}{\#\,\text{channels}}\cdot
\frac{W_\text{pair}[\text{eV}]}{E_\text{particle}[\text{keV}]}\cdot
\frac{1}{(\text{coarse\,gain})\cdot
(\text{fine\,gain})}\cdot
\frac{10^6}   {X[\text{mV}]\cdot E_{cg}[\text{eV}]}
\label{eq:Gain}
\end{gather}
\end{document}

Also I have used the fonts Latin Modern instead of Computer Modern, because the kerning of eV is much better there.

Answer 3

Now this is a different approach. Practically I am cheating a bit by forcing LaTeX to ignore any proper page settings and go into the margins to fit the equation and its number into one line. I (ab)use the adjmulticol package for this to happen. Then everything return to normal:

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{lipsum}
\usepackage{adjmulticol}
\begin{document}
\lipsum[1]
\begin{adjmulticols}{1}{-2cm}{-2cm}
\begin{equation}
{\footnotesize G=centroid\cdot \frac{range[V]}{\#\,channels}\cdot\frac{W_{pair}[eV]}    {E_{particle}[keV]}\cdot \frac{1}{(coarse\,gain)\cdot(fine\,gain)}\cdot \frac{10^6}   {X[mV]\cdot E_{cg}[eV]}}
\label{eq:Gain}
\end{equation}
\end{adjmulticols}
\lipsum[2]
\end{document}