My code generated unwanted page break once I start the align environment. The best way to show it, is to provide the relevant code so someone can compile it.
My code looks like this
\documentclass[a4paper]{article}
\usepackage[hmargin=2.5cm,vmargin=1cm]{geometry}
\usepackage{parskip}
\usepackage{amsmath}
\begin{document}
\section{Derivations}
\subsection{Derivations2}
bla bla
\begin{equation}
c^i_1 + \frac{c^i_2}{1+r} + (n-r)\frac{x^i}{1+r} = wl^i -\tau
\end{equation}
\begin{align}
& d(c^i_1) + d(\frac{c^i_2}{1+r}) + d((n-r)\frac{x^i}{1+r}) = d(wl^i) -d(\tau) \\
& d(c^i_1) + \big[c^i_2 d(\frac{1}{1+r}) + \frac{1}{1+r} dc^i_2 \big] + \big[x^i d(\frac{n-r}{1+r}) + \frac{n-r}{1+r} dx^i \big]= d(wl^i) -d(\tau) \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) - c^i_2 d(\frac{1}{1+r}) - x^i d(\frac{n-r}{1+r}) \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) - c^i_2 d(\frac{1}{1+r}) - x^i (n-r)d(\frac{1}{1+r}) - \frac{x^i}{1+r}d(n-r) \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) - c^i_2 d(\frac{1}{1+r}) - x^i (n-r)d(\frac{1}{1+r}) + \frac{x^i}{1+r}dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) - \left[c^i_2 + x^i (n-r) \right]d(\frac{1}{1+r}) + \frac{x^i}{1+r}dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \frac{\left[c^i_2 + x^i (n-r) \right]}{(1+r)^2}d(r) + \frac{x^i}{1+r}dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \bigg( \frac{1}{1+r}\bigg)\frac{\left[c^i_2 + x^i (n-r) \right]}{(1+r)}dr + \frac{x^i}{1+r}dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \bigg( \frac{1}{1+r}\bigg)(wl^i -\tau - c^i_1)d(r) + \frac{x^i}{1+r}dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \bigg( \frac{1}{1+r}\bigg)(\underbrace{wl^i + x^i -\tau - c^i_1}_{s^i})dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \bigg( \frac{s^i}{1+r}\bigg) dr \\
& d(c^i_1) + \frac{1}{1+r} dc^i_2 + \frac{n-r}{1+r} dx^i = d(wl^i) -d(\tau) + \bigg( \frac{s^i}{1+r}\bigg) dr + \bigg( \frac{S}{1+r}\bigg)dr - \bigg( \frac{S}{1+r}\bigg)dr \\
& = d(wl^i) - d(\tau) + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = d(wl^i) - d[(r-n)b] + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = d(wl^i) - d[(r-n)b] + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = l^i dw - \left[(r-n)db + bdr \right] + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = l^i (-k) dr - \left[(r-n)db + bdr \right] + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = - l^i k dr - (r-n)db - bdr - kdr + kdr + \bigg( \frac{S}{1+r}\bigg)dr + \bigg( \frac{s^ i - S}{1+r}\bigg)dr \\
& = k (1-l^i)dr - (k+b)dr - (r-n)db + \bigg( \frac{S}{1+r}\bigg)dr + \big( \frac{s^ i - S}{1+r}\big)dr \\
& = - (k+b)dr - (r-n)db + \bigg( \frac{S}{1+r}\bigg)dr + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \\
& = - \bigg[(k+b) - \big(\frac{S}{1+r}\big) \bigg]dr - (r-n)db + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \label{total change in life-cycle budget in general}\\
& = - \bigg[(k+b) - \big(\frac{(1+n)(k+b)}{1+r}\big) \bigg]dr - (r-n)db + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \\
& = - \bigg[k + b - \frac{(1+n)k}{1+r} - \frac{(1+n)b}{1+r}\bigg]dr - (r-n)db + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \\
& = - \bigg[\left(k - \frac{(1+n)k}{1+r}\right) + \left( b- \frac{(1+n)b}{1+r}\right)\bigg]dr - (r-n)db + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \\
& = - \frac{r-n}{1+r} (k+b) dr - (r-n)db + \bigg[\big( \frac{s^ i - S}{1+r}\big) + k(1-l^i)\bigg] dr \label{total effect in the life-cycle budget}
\end{align}
\end{document}
I understand that LaTeX, since I have the align environment, tries to fit it in one page, but this leaves the other page almost empty. Is there a way to fix it? Any help will be much appreciated.
\allowdisplaybreaksand\displaybreakin the amsmath documentation amsldoc. You can also enlarge the page with\enlargethispage. – Ulrike Fischer Oct 30 '13 at 13:57\end{align}and\begin{align}again where the break is wanted. – doed Nov 24 '13 at 23:26