Auto Breaking of Long Equations

Question

There is the package breqn for automatically breaking long math equations. I have used it, but there are three problems that I am facing.

• First: How can I implement the "Drop Ladder Layout", described in the package documentation of breqn?
• Second: How can I reach a ragged-right alignment of the rhs in the equation?
• Third: How can I implement a pagebreak within breqn?

Thanks, Peter

Here is the code containing the problems:

\documentclass[10pt, a5paper]{article}
\usepackage{amsmath}
\usepackage[]{breqn}

\renewcommand\[{\begin{dmath}}
\renewcommand\]{\end{dmath}}

%\allowdisplaybreaks
%\interdisplaylinepenalty=0

\begin{document}

\[
P_{5 \text{,}\: avg\text{,}\: var1}\left(T_1\right) 
= \left( \lambda _{DU}+\lambda _{DD} \right) \lambda _{DR}\,T_{1}
+\left(  \left( -\frac{1}{2}\,\mu _{0}\,\lambda _{DD}-\frac{1}{3}\,{\lambda _{DD}}^{2}   -\lambda _{DU}\,\lambda _{DD}-\frac{1}{4}\,\lambda _{DD}\,\mu _{DR}
-\frac{1}{5}\,{\lambda _{DU}}^{2}-\frac{1}{6}\,\lambda _{DU}\,\mu _{DR}
-\frac{1}{7}\,\mu _{LT}\,\lambda _{DU} \right) \lambda _{DR}
-\left( \frac{1}{8}\,\lambda _{DU}+\frac{1}{9}\,\lambda _{DD} \right) {\lambda _{DR}}^{2} \right) {T_{1}}^{2}
 + \left(  \left( \frac{1}{10}\,\lambda _{DD}\,{\mu _{0}}^{2}+\frac{1}{20}\,\mu _{0}\,{\lambda _{DD}}^{2} 
 +\frac{1}{30}\,\mu _{0}\,\lambda _{DU}\,\lambda _{DD}+\frac{1}{40}\,{\lambda _{DD}}^{3}
 +\frac{1}{50}\,\lambda _{DU}\,{\lambda _{DD}}^{2}+\,\frac{1}{60}\,{\lambda _{DD}}^{2}\,\mu _{DR} 
 +\frac{1}{70}\,{\lambda _{DU}}^{2}\,\lambda _{DD}+\frac{1}{80}\,\lambda _{DU}\,\lambda _{DD}\,\mu _{DR}
 +\frac{1}{90}\,\lambda _{DD}\,\mu _{LT}\,\lambda _{DU}+\frac{1}{100}\,\lambda _{DD}\,{\mu _{DR}}^{2} 
 +\frac{1}{110}\,{\lambda _{DU}}^{3}+\frac{1}{120}\,{\lambda _{DU}}^{2}\,\mu _{DR} 
 +\frac{1}{130}\,\mu _{LT}\,{\lambda _{DU}}^{2}+\frac{1}{140}\,\lambda _{DU}\,{\mu _{DR}}^{2}  
 +\frac{1}{150}\,{\mu _{LT}}^{2}\,\lambda _{DU} \right) \lambda _{DR} 
 +\left( \frac{1}{160}\,\lambda _{DD}\,\mu _{0}+\frac{1}{170}\,{\lambda _{DD}}^{2}
 +\frac{1}{180}\,\lambda _{DU}\,\lambda _{DD}+\frac{1}{190}\,\lambda _{DD}\,\mu _{DR} 
 +\frac{1}{200}\,{\lambda _{DU}}^{2}+\frac{1}{210}\,\lambda _{DU}\,\mu _{DR} 
 +\frac{1}{220}\,\mu _{LT}\,\lambda _{DU} \right) {\lambda _{DR}}^{2} 
 +\left(\frac{1}{230}\, \lambda _{DU}+\frac{1}{240}\,\lambda _{DD}\right) {\lambda _{DR}}^{3} \right) {T_{1}}^{3} \text{.}
\]

\end{document}

Answer 1

I don't think you can get a nice result with any package. With breqn, instead, it's almost impossible.

\documentclass[10pt, a5paper]{article}
\usepackage{amsmath}

\begin{document}

\begin{flushleft}
\linespread{2.5}\selectfont
\leftskip=3em
\hspace*{-3em}$\displaystyle
P^{}_{5,\,\mathrm{avg},\, \mathrm{var}1}(T_1) 
= ( \lambda _{DU}+\lambda _{DD} ) \lambda _{DR}T_{1}
+\biggl(  \biggl( -\frac{1}{2}\mu _{0}\lambda _{DD}-\frac{1}{3}{\lambda _{DD}}^{2}
-\lambda _{DU}\lambda _{DD}-\frac{1}{4}\lambda _{DD}\mu _{DR}
-\frac{1}{5}{\lambda _{DU}}^{2}-\frac{1}{6}\lambda _{DU}\mu _{DR}
-\frac{1}{7}\mu _{LT}\lambda _{DU} \biggr) \lambda _{DR}
-\biggl( \frac{1}{8}\lambda _{DU}+\frac{1}{9}\lambda _{DD} \biggr)
  {\lambda _{DR}}^{2} \biggr) {T_{1}}^{2}
+ \biggl(  \biggl( \frac{1}{10}\lambda _{DD}{\mu _{0}}^{2}
+\frac{1}{20}\mu _{0}{\lambda _{DD}}^{2} 
+\frac{1}{30}\mu _{0}\lambda _{DU}\lambda _{DD}+\frac{1}{40}{\lambda _{DD}}^{3}
+\frac{1}{50}\lambda _{DU}{\lambda _{DD}}^{2}+\frac{1}{60}{\lambda _{DD}}^{2}\mu _{DR} 
+\frac{1}{70}{\lambda _{DU}}^{2}\lambda _{DD}+\frac{1}{80}\lambda _{DU}\lambda _{DD}\mu _{DR}
+\frac{1}{90}\lambda _{DD}\mu _{LT}\lambda _{DU}+\frac{1}{100}\lambda _{DD}{\mu _{DR}}^{2} 
+\frac{1}{110}{\lambda _{DU}}^{3}+\frac{1}{120}{\lambda _{DU}}^{2}\mu _{DR} 
+\frac{1}{130}\mu _{LT}{\lambda _{DU}}^{2}+\frac{1}{140}\lambda _{DU}{\mu _{DR}}^{2}  
+\frac{1}{150}{\mu _{LT}}^{2}\lambda _{DU} \biggr) \lambda _{DR} 
+\biggl( \frac{1}{160}\lambda _{DD}\mu _{0}+\frac{1}{170}{\lambda _{DD}}^{2}
+\frac{1}{180}\lambda _{DU}\lambda _{DD}+\frac{1}{190}\lambda _{DD}\mu _{DR} 
+\frac{1}{200}{\lambda _{DU}}^{2}+\frac{1}{210}\lambda _{DU}\mu _{DR} 
+\frac{1}{220}\mu _{LT}\lambda _{DU} \biggr) {\lambda _{DR}}^{2} 
+\biggl(\frac{1}{230} \lambda _{DU}+\frac{1}{240}\lambda _{DD}\biggr)
  {\lambda _{DR}}^{3} \biggr) {T_{1}}^{3}.
$
\end{flushleft}

\end{document}

It's ugly as well, but less horrible than what you get with breqn. And it breaks across pages.

Note. I removed all \, that serve no purpose; it's not clear why typing {T_{1}}^{2} instead of the customary T_{1}^{2}. In particular, {\lambda_{DD}}^{2} results in a very unclear output, because the superscript seems rather to DD than to \lambda_{DD}.