添加一段描述性文字
\[t+1=2\]
\[ \mbox{积累因子}=\begin{cases} 1+ni & \mbox{单利}\\\\ (1+i)^n & \mbox{复利} \end{cases} \]
\[ \begin{equation} \sum_{i=0}^n F_i \cdot \phi (H, p_i) - \sum_{i=1}^n a_i \cdot ( \tilde{x_i}, \tilde{y_i}) + b_i \cdot ( \tilde{x_i}^2 , \tilde{y_i}^2 ) \end{equation} \] \[ \begin{equation} \beta^*(D) = \mathop{argmin} \limits_{\beta} \lambda {||\beta||}^2 + \sum_{i=1}^n max(0, 1 - y_i f_{\beta}(x_i)) \end{equation} \]
