【动手学深度学习】|线性神经网络-2

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前言

学习资源在
预备知识整理-1

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一、求导方法

链式法则：
$$\frac{\partial y}{\partial x}=\frac{\partial y}{\partial u_n}\frac{\partial u_n}{\partial u_{n-1}}...\frac{\partial u_2}{\partial u_1}\frac{\partial u_1}{\partial x}$$
正向累积
∂ y ∂ x = ∂ y ∂ u n ( ∂ u n ∂ u n − 1 ( . . . ( ∂ u 2 ∂ u 1 ∂ u 1 ∂ x ) ) ) \frac{\partial y}{\partial x}=\frac{\partial y}{\partial u_n}(\frac{\partial u_n}{\partial u_{n-1}}(...(\frac{\partial u_2}{\partial u_1}\frac{\partial u_1}{\partial x}))) ∂x∂y​=∂un​∂y​(∂un−1​∂un​​(...(∂u1​∂u2​<