\begin{equation}
R_{SU_1}^{(e)} =
\begin{cases}
\frac{1}{ln2}\bigg[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s,max
答案1
您的公式太长,无法适应标准边距,因此您必须将其拆分。为了方便起见,我加载了包geometry
以获得更合理的边距(如果您不使用边距注释)。我建议使用以下两种布局之一,并使用更简单的代码:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[showframe]{geometry}
\usepackage{mathtools}
\usepackage{amssymb}
\begin{document}
\begin{equation}
\begin{split}
\MoveEqLeft R_{SU_1}^{(e)} = \frac{1}{\ln2}\times \\
& \begin{cases}
\biggl[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s \max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s,\max}}} \mathrlap{\bigl [ye^yEi(-y)+1\bigr] \biggr]} \\ & \text{if $x = 1$ i.e., $\lambda_{s,p}\alpha I_{th} = \sigma^2$}\\
\biggl[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s, \max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s, \max}}}\mathrlap{\bigl[e^{xy}Ei(-xy)-e^yEi(-y)\bigr]\biggr]} \\ & \text{if $x \neq 1$, i.e., $\lambda_{s,p}\alpha I_{th} \neq \sigma^2$}
\end{cases}
\end{split}
\label{u1}
\end{equation}
\vskip 1cm
\begin{equation}
\begin{split}
R_{SU_1}^{(e)} = \frac{1}{\ln2} \biggl[ & {-}e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s \max}}}e^\mu E_i(\mu) \\[-1ex]
& +x e^{-\frac{I\lambda_{s,p}}{P_{s,\max}}}\times\begin{cases}
\bigl [ye^yEi(-y)+1\bigr] \biggr] & \text{if $x = 1$ i.e., $\lambda_{s,p}\alpha I_{th} = \sigma^2$}\\
\bigl[e^{xy}Ei(-xy)-e^yEi(-y)\bigr]\biggr] & \text{if $x \neq 1$, i.e., $\lambda_{s,p}\alpha I_{th} \neq \sigma^2$}
\end{cases}
\end{split}
\label{u1}
\end{equation}
\end{document}
答案2
这两个分支中的公式非常相似,因此我会选择以下其中之一:
代码如下:
\documentclass{article}
\usepackage{mathtools}
\usepackage{amssymb}
\begin{document}
\noindent Define
\[
R(x,y,z) = \frac1{\ln2}
\biggl[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s, \max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s, \max}}}{\bigl[e^{xy}Ei(-xy)+z\bigr]\biggr]}
\]
Then
\begin{equation}\label{E:}
R_{SU_1}^{(e)} =
\begin{cases*}
R(x,y,z)&if $x = 1$ i.e., $\lambda_{s,p}\alpha I_{th} = \sigma^2$\\
R(x,y,-e^yEi(-y))&if $x \neq 1$, i.e., $\lambda_{s,p}\alpha I_{th} \neq \sigma^2$
\end{cases*}
\end{equation}
\textit{\dotfill or\dotfill}
\noindent Define
\[
R(x) = \frac1{\ln2}
\biggl[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s, \max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s, \max}}}\biggr]
\]
Then
\begin{equation}\label{E:}
R_{SU_1}^{(e)} =
\begin{cases*}
R(x)\bigl[e^{xy}Ei(-xy)+1\bigr]
&if $x = 1$ i.e., $\lambda_{s,p}\alpha I_{th} = \sigma^2$\\
R(x)\bigl[e^{xy}Ei(-xy)-e^yE_i(-y)\bigr]
&if $x \neq 1$, i.e., $\lambda_{s,p}\alpha I_{th} \neq \sigma^2$
\end{cases*}
\end{equation}
\end{document}
注意\ln2
并使用cases*
环境从数学工具包裹。
答案3
就像 esdd 在评论中所说,您需要删除\nonumber
和空行:
\begin{equation}
R_{SU_1}^{(e)} =
\begin{cases}
\frac{1}{ln2}\bigg[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s,max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s,max}}} [ye^yEi(-y)+1] \bigg] & \\ \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \text{if $x = 1$ i.e., $\lambda_{s,p}\alpha I_{th} = \sigma^2$}\\
\frac{1}{ln2}\bigg[ -e^\mu E_i(\mu)+e^{\frac{I \lambda_{s,p}}{P_{s,max}}}e^\mu E_i(\mu)+x e^{-\frac{I\lambda_{s,p}}{P_{s,max}}}[e^{xy}Ei(-xy)-e^yEi(-y)] & \\ \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \text{if $x \neq 1$, i.e., $\lambda_{s,p}\alpha I_{th} \neq \sigma^2$}\\
\end{cases}
\label{u1}
\end{equation}
就像\nonumber
它本身所说的那样,它将阻止对方程式进行编号