【826】Latex 大括号多行公式写法

参考：Latex大括号及多行公式

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方法一：

\begin{equation}
    \begin{cases}
    \delta_1 = sin^2{\left ( \frac{\varphi_2 - \varphi_1}{2} \right )}, \\
    \delta_2 = cos(\varphi_1) \cdot cos(\varphi_2) \cdot sin^2{\left ( \frac{\lambda_2 - \lambda_1}{2} \right )}, \\
    D = 2 \cdot R \cdot arcsin \left ( \sqrt{\delta_1 + \delta_2} \right), 
    \end{cases}
\end{equation}

方法二：

\begin{equation}  
\left\{  
     \begin{array}{lr}  
     \delta_1 = sin^2{\left ( \frac{\varphi_2 - \varphi_1}{2} \right )}, &  \\  
     \delta_2 = cos(\varphi_1) \cdot cos(\varphi_2) \cdot sin^2{\left ( \frac{\lambda_2 - \lambda_1}{2} \right )}, & \\  
     D = 2 \cdot R \cdot arcsin \left ( \sqrt{\delta_1 + \delta_2} \right), &    
     \end{array}  
\right.  
\end{equation} 

效果：（上面代码位置调换了）