# Splitting the denominator of fraction into more than two lines

I wish to split the denominator of the following fraction into more than 2 lines. For splitting into two lines, splitfraccan be used. But how to split the denominator into three lines?

\documentclass{article}
\usepackage{mathtools}
\begin{document}
$$\label{eq31} G_2(s) = \frac{K_pcT_rs+K_p}{\splitfrac{T_pT_rT_pT_ts^4 + \left(T_gT_pT_t + T_gT_pT_r + T_pT_tT_r + T_gT_rT_t\right)s^3}{ + \left(T_pT_g + T_tT_g + T_rT_g + T_tT_p + T_rT_p + T_rT_t\right)s^2+\left(T_g + T_r + T_t + T_p\right)s + 1 }}$$
\end{document}

• as always on this site, please provide a full minimal example instead of a sniplet like this. That makes it a lot easier for others to have a look at your code – daleif Apr 25 at 12:59
• BTW: I would not use \splitfrac here, I'd just use the aligned environment. Plus those \left/right constructions does nothing here. – daleif Apr 25 at 13:00
• Please see the Minimal example – ShiS Apr 25 at 13:03
• The aforementioned link deals with breaking of equation into two lines only, while I prefer to break it into more than two lines – ShiS Apr 26 at 2:01

I believe that my answer is based on a personal and aesthetic taste. I prefer to split your denominator with a matrix or an array. I have also put geometry package to have more margin in the page. I think that by minimizing the margins, option that I do not recommend since the printing of the page could crop the formulas, all your formula could be built in a single line.
Here into my MWE I have split the denominator into three lines with matrix:
\documentclass{article}
$$\label{2} G_2(s) =\frac{K_pcT_rs+K_p}{\begin{matrix}T_pT_rT_pT_ts^4 +(T_gT_pT_t + T_gT_pT_r + T_pT_tT_r + T_gT_rT_t)s^3 &\\+(T_pT_g + T_tT_g + T_rT_g + T_tT_p + T_rT_p + T_rT_t)s^2&\\+(T_g + T_r + T_t + T_p)s + 1\end{matrix}}$$