测试页面

$\sqrt{公式}$

\[\left[ \begin{array}{a} a^l_1 \\ ⋮ \\ a^l_{d_l} \end{array}\right] = \sigma( \left[ \begin{matrix} w^l_{1,1} & ⋯ & w^l_{1,d_{l-1}} \\ ⋮ & ⋱ & ⋮ \\ w^l_{d_l,1} & ⋯ & w^l_{d_l,d_{l-1}} \\ \end{matrix}\right] · \left[ \begin{array}{x} a^{l-1}_1 \\ ⋮ \\ ⋮ \\ a^{l-1}_{d_{l-1}} \end{array}\right] + \left[ \begin{array}{b} b^l_1 \\ ⋮ \\ b^l_{d_l} \end{array}\right]) \]

\[\mathbb{E}(X) = \int x d F(x) = \left\{ \begin{aligned} \sum_x x f(x) \; & \text{ if } X \text{ is discrete} \\ \int x f(x) dx \; & \text{ if } X \text{ is continuous } \end{aligned} \right. \]

Inline math \(\frac{1}{2}\).

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