# How to prevent font size in condition equation from getting changed [duplicate]

Below is a snippet of my latex source that prints an equation. In the attached image output, I see a significant decrease in font size in the part of the equation that is represented as in the numerator/denominator form.

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$P[Y=l]= \begin{cases} \mu(lm+\mu)^{l-1}\frac{{e^{-lm-\mu}}}{r!(1-e^{-\mu})}}; & 1\leq l < M\\ 1-\sum_{s=1}^{M-1}\mu(sm+\mu)^{s-1}\frac{{e^{-sm-\mu}}}{s!(1-e^{-\mu})}; & l=M }\\ \end{cases} \eqno{\hbox{(11)}}\\$
\end{document}


Can I force latex to print all parts of the equation in the same font size?

thanks

• Yes. Use \displaystyle\frac{}{} – Sigur Dec 18 '14 at 16:56
• Your document produces the error ! Extra }, or forgotten \$. If you carry on after an error only use the resulting pdf for debugging purposes TeX does not attempt to produce reasonable output, just to get out of an error state – David Carlisle Dec 18 '14 at 16:59
• \usepackage{mathtools} in the preamble and \begin{dcases}...\end{dcases} instead of cases. Never use \eqno with LaTeX. – egreg Dec 18 '14 at 16:59