多种数学环境公式的对比¶ equation¶ \[ \begin{equation} \sum_{i=1}^n a_i = 0 \end{equation} \] align¶ \[ \begin{align} \sum_{i=1}^n a_i &= 0 \\ \sum_{i=1}^n b_i &= 0 \end{align} \]