书写巨大单数表达式的理想方式是什么？

Question

考虑：

\documentclass[12pt,a4paper,oneside]{book}
\usepackage[a4paper,width=150mm,top=30mm,bottom=30mm,bindingoffset=6mm]{geometry}
\usepackage{amsfonts, graphicx, verbatim, mathtools,amssymb, amsthm, mathrsfs,amsmath}
\begin{document}
\begin{align*}
&\lim\limits_{t \rightarrow \infty} \inf \langle I(t) \rangle \geq\frac{(\mu+\rho(1-e^{-\mu\tau_1})+\xi)\Big[\beta(1-\rho)(1-\xi)f(S_0)(g'(0)-\delta)-\Big((\mu+\alpha+\theta+\gamma)+\frac{\sigma_2^2}{2}+\displaystyle\int_M [D_2(y)-\log(1+D_2(y))]\nu(dy)\Big) \Big]}{\beta(1-\rho)(1-\xi)(g'(0)-\delta)\max\limits_{0\leq k\leq S_0}f'(k)(\mu+\alpha+\theta(1-e^{-\mu\tau_2})+\gamma(1-e^{-\mu\tau_3}))}
\end{align*}
\end{document}

理想的书写方式是什么，以致它不会超出页面范围？

Answer 1

\documentclass[12pt,a4paper,oneside]{book}
\usepackage[a4paper,width=150mm,top=30mm,bottom=30mm,bindingoffset=6mm]{geometry}
\usepackage{amsfonts, graphicx, verbatim, mathtools,amssymb, amsthm, mathrsfs,amsmath}
\begin{document}
\[
\lim_{t \rightarrow \infty} \inf \langle I(t) \rangle \geq \frac{A}{B}\\
\]
where
\begin{align*}
A&=
(\mu+\rho(1-e^{-\mu\tau_1})+\xi)\Bigl[\beta(1-\rho)(1-\xi)f(S_0)(g'(0)-\delta)\\
&\qquad -\Bigl((\mu+\alpha+\theta+\gamma)+\frac{\sigma_2^2}{2}+\int_M [D_2(y)-\log(1+D_2(y))]\nu(dy)\Bigr) \Bigr]\\[\jot]
B&=\beta(1-\rho)(1-\xi)(g'(0)-\delta)\max_{0\leq k\leq S_0}f'(k)(\mu+\alpha+\theta(1-e^{-\mu\tau_2})+\gamma(1-e^{-\mu\tau_3}))
\end{align*}
\end{document}