我想在 Theorem 环境下编写以下文本和数学表达式。我希望它们都左对齐。
你能指导我怎样做吗？
\begin{theorem}
The marginal distribution of `$\hat{\theta}_2$, for $-\infty<y<\infty$` is
\begin{eqnarray*}
\begin{split}
f_{\hat{\theta}_2}(y)&=k\binom{n}{k} \sum_{i=0}^{k-1}\frac{\binom{k-1}{i}(-1)^i}{(n-k+1+i)}e^{-\frac{T}{\theta_1}(n-k+1+i)}f_g(y;n-k,\frac{n-k}{\theta_2})\\
&+\sum_{i=k}^{m-1}\sum_{s=0}^i\binom{n}{i}\binom{i}{s}(-1)^s e^{-\frac{T}{\theta_1} (n-i+s)} f_g(y;n-i,\frac{n-i}{\theta_2})+m\binom{n}{m}\times\\
&\sum_{i=0}^{m-1} \frac{\binom{m-1}{i}(-1)^i}{n-m+1+i} [1-e^{-\frac{T}{\theta_1}(n-m+1+i)}]f_g(y;n-m,\frac{(n-m)}{\theta_2}
\end{split}
\end{eqnarray*}
\end{theorem}
答案1
您可以使用flalign*环境来做到这一点。但我建议也使用环境multline*。以下代码显示了可能性，并对换行点进行了一些修改。我还更改了一些括号的大小：
\documentclass{article}
\usepackage[utf8]{inputenc} %
\usepackage[showframe]{geometry}%
\usepackage{mathtools,nccmath, amsthm}
\usepackage{amsfonts}
\newtheorem{theorem}{Theorem}
\begin{document}
\begin{theorem}
The marginal distribution of $\hat{\theta }_2$, for $-\infty<y<\infty$ is
\begin{flalign*}
f_{\hat{\theta }_2}(y)=k\binom{n}{k} & \smash[t]{\sum_{i=0}^{k-1}\frac{\binom{k-1}{i}(-1)^i}{(n-k+1+i)}e^{-\frac{T}{\theta_1}(n-k+1+i)}f_g\biggl(y;n-k,\frac{n-k}{\theta_2}\biggr)} & & & \\
{}+{}&\sum_{i=k}^{\mathclap{m-1}}\sum_{s=0}^i\binom{n}{i}\binom{i}{s}(-1)^s e^{-\frac{T}{\theta_1} (n-i+s)} f_g\biggl(y;n-i,\frac{n-i}{\theta_2}\biggr)\\
{}+{}&m\binom{n}{m}\sum_{i=0}^{m-1} \frac{\binom{m-1}{i}(-1)^i}{n-m+1+i} \Bigl[1-e^{-\frac{T}{\theta_1}(n-m+1+i)}\Bigr]f_g\biggl(y;n-m,\frac{n-m}{\theta_2}\biggr)
\end{flalign*}
\end{theorem}
\bigskip
\begin{theorem}
The marginal distribution of $\hat{\theta }_2$, for $-\infty<y<\infty$ is
\begin{multline*}
f_{\hat{\theta }_2}(y)=\smash[t]{k\binom{n}{k} \sum_{i=0}^{k-1}\frac{\binom{k-1}{i}(-1)^i}{(n-k+1+i)}e^{-\frac{T}{\theta_1}(n-k+1+i)}f_g\biggl(y;n-k,\frac{n-k}{\theta_2}\biggr)} \\
{}+\sum_{i=k}^{\mathclap{m-1}}\sum_{s=0}^i\binom{n}{i}\binom{i}{s}(-1)^s e^{-\frac{T}{\theta_1} (n-i+s)} f_g\biggl(y;n-i,\frac{n-i}{\theta_2}\biggr)\\
{}+m\binom{n}{m}\sum_{i=0}^{m-1} \frac{\binom{m-1}{i}(-1)^i}{n-m+1+i} \Bigl[1-e^{-\frac{T}{\theta_1}(n-m+1+i)}\Bigr]f_g\biggl(y;n-m,\frac{n-m}{\theta_2}\biggr)
\end{multline*}
\end{theorem}
\bigskip
\begin{theorem}
The marginal distribution of $\hat{\theta }_2$, for $-\infty<y<\infty$ is
\begin{fleqn}
\begin{align*}
& f_{\hat{\theta }_2}(y)=\smash[t]{k\binom{n}{k} \sum_{i=0}^{k-1}\frac{\binom{k-1}{i}(-1)^i}{(n-k+1+i)}e^{-\frac{T}{\theta_1}(n-k+1+i)}f_g\biggl(y;n-k,\frac{n-k}{\theta_2}\biggr)} \\
& \negthickspace+\sum_{i=k}^{\mathclap{m-1}}\sum_{s=0}^i\binom{n}{i}\binom{i}{s}(-1)^s e^{-\frac{T}{\theta_1} (n-i+s)} f_g\biggl(y;n-i,\frac{n-i}{\theta_2}\biggr)\\
& \negthickspace+m\binom{n}{m}\sum_{i=0}^{m-1} \frac{\binom{m-1}{i}(-1)^i}{n-m+1+i} \Bigl[1-e^{-\frac{T}{\theta_1}(n-m+1+i)}\Bigr]f_g\biggl(y;n-m,\frac{n-m}{\theta_2}\biggr) \end{align*}
\end{fleqn}%
\end{theorem}%
\end{document}
