(\partial)/(\partial x)(x/(x^2+25))

解答

\frac{\partial}{\partial x} (\frac{x}{x ^{2} + 25})

\frac{- x ^{2} + 25}{( x ^{2} + 25 ) ^{2}}

求解步骤

\frac{\partial}{\partial x} (\frac{x}{x ^{2} + 25})

使用微分除法定则:

(\frac{f}{g})^{'} = \frac{f ^{'} \cdot g - g ^{'} \cdot f}{g ^{2}}

= \frac{\frac{\partial}{\partial x} ( x ) ( x ^{2} + 25 ) - \frac{\partial}{\partial x} ( x ^{2} + 25 ) x}{( x ^{2} + 25 ) ^{2}}

\frac{\partial}{\partial x} (x) = 1

\frac{\partial}{\partial x} (x^{2} + 25) = 2 x

= \frac{1 \cdot ( x ^{2} + 25 ) - 2 xx}{( x ^{2} + 25 ) ^{2}}

1 \cdot (x^{2} + 25) - 2 xx = - x^{2} + 25

= \frac{- x ^{2} + 25}{( x ^{2} + 25 ) ^{2}}