$$ \pi(\tau|x)= \frac{ B(S_{\tau}+a,b) \,_2F_1(S_{\tau}+\tau r, S_{\tau}+a, S_{\tau}+a+b; -\frac{1}{r})}
{\sum_{\tau=1}^{n} B(S_{\tau}+a,b) \,_2F_1(S_{\tau}+\tau r, S_{\tau}+a, S_{\tau}+a+b; -\frac{1}{r})} $$
\begin{equation}
\times \frac{B(S_{n-\tau}+a_1,b_1) \,_2F_1(S_{n-\tau}+(n-\tau) r, S_{n-\tau}+a_1, S_{n-\tau}+a_1+b_1; -\frac{1}{r}) }{B(S_{n-\tau}+a_1,b_1) \,_2F_1(S_{n-\tau}+(n-\tau) r, S_{n-\tau}+a_1, S_{n-\tau}+a_1+b_1; -\frac{1}{r})}
\end{equation}
答案1
我假设您希望将两个方程合并为一个两行方程。在这种情况下,使用包amsmath
或mathtools
(的改进版本amsmath
)及其数学环境(如等multline
)align
非常方便:
\documentclass{article}
\usepackage[margin=30mm]{geometry}
\usepackage{mathtools}
\usepackage{showframe}% for show page layout, in real use had to be omitted
\renewcommand*\ShowFrameColor{\color{red}}
\begin{document}
\begin{multline}
\pi(\tau|x) =
\frac{B(S_{\tau}+a,b)_2 F_1(S_{\tau}+\tau r, S_{\tau}+a, S_{\tau}+a+b; -\frac{1}{r})}
{\sum\limits_{\tau=1}^{n} B(S_{\tau}+a,b)_2
F_1(S_{\tau}+\tau r, S_{\tau}+a, S_{\tau}+a+b; -\frac{1}{r})}
\times\\
\frac{B(S_{n-\tau}+a_1,b_1)_2F_1(S_{n-\tau}+(n-\tau)r, S_{n-\tau}+a_1, S_{n-\tau}+a_1+b_1; -\frac{1}{r}) }
{B(S_{n-\tau}+a_1,b_1)_2F_1(S_{n-\tau}+(n-\tau)r, S_{n-\tau}+a_1, S_{n-\tau}+a_1+b_1; -\frac{1}{r})}
\end{multline}
or
\begin{equation}
\pi(\tau|x) =
\frac{B(S_{\tau}+a,b)_2 F_1(S,\tau,r)}
{\sum\limits_{\tau=1}^{n} B(S_{\tau}+a,b)_2 F_1(S,\tau,r)} \times
\frac{B(S_{n-\tau}+a_1,b_1)_2F_1(S,n,\tau,r)}
{B(S_{n-\tau}+a_1,b_1)_2F_1(S,n,\tau,r)}
\end{equation}
where
\begin{align*}
F_1(S,\tau,r) & = F_1(S_{\tau}+\tau r, S_{\tau}+a, S_{\tau}+a+b; -\frac{1}{r})\\
F_1(S,n,\tau,r) & = F_1(S_{n-\tau}+(n-\tau)r, S_{n-\tau}+a_1, S_{n-\tau}+a_1+b_1; -\frac{1}{r})
\end{align*}
\end{document}
请注意,等式的第二部分等于 1:)(或者其中存在一些错误)。