미분1 sigmoid, tanh 함수 미분 Logistic Sigmoid (Activation) Function 미분 $$g\left(a\right) = \frac{1}{1+e^{-a}}$$ Using $$ \frac{d}{dx} \left( \frac{u}{v} \right) = \frac{v\left(du/dx\right) - u\left(dv/dx\right)}{v^{2}},$$ $$ g'\left(a\right) = \frac{e^{-a}}{\left( 1 + e^{-a} \right)^2} = \frac{1 + e^{-a} - 1}{\left( 1 + e^{-a} \right)^2} = \frac{1}{\left( 1 + e^{-a} \right)} - \frac{1}{\left( 1 + e^{-a} \right)^2}$$ $$= \fr.. 2015. 3. 27. 이전 1 다음
