derivative of (x^4+3x^2/((x^2+1)^2))

解答

\frac{d}{d x} (\frac{x ^{4} + 3 x ^{2}}{( x ^{2} + 1 ) ^{2}})

\frac{2 x ( - x ^{2} + 3 )}{( x ^{2} + 1 ) ^{3}}

求解步骤

\frac{d}{d x} (\frac{x ^{4} + 3 x ^{2}}{( x ^{2} + 1 ) ^{2}})

使用微分除法定则:

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

= \frac{\frac{d}{d x} ( x ^{4} + 3 x ^{2} ) ( x ^{2} + 1 ) ^{2} - \frac{d}{d x} ( ( x ^{2} + 1 ) ^{2} ) ( x ^{4} + 3 x ^{2} )}{( ( x ^{2} + 1 ) ^{2} ) ^{2}}

\frac{d}{d x} (x^{4} + 3 x^{2}) = 4 x^{3} + 6 x

\frac{d}{d x} ((x^{2} + 1)^{2}) = 4 x (x^{2} + 1)

= \frac{( 4 x ^{3} + 6 x ) ( x ^{2} + 1 ) ^{2} - 4 x ( x ^{2} + 1 ) ( x ^{4} + 3 x ^{2} )}{( ( x ^{2} + 1 ) ^{2} ) ^{2}}

化简

\frac{( 4 x ^{3} + 6 x ) ( x ^{2} + 1 ) ^{2} - 4 x ( x ^{2} + 1 ) ( x ^{4} + 3 x ^{2} )}{( ( x ^{2} + 1 ) ^{2} ) ^{2}} : \frac{2 x ( - x ^{2} + 3 )}{( x ^{2} + 1 ) ^{3}}

= \frac{2 x ( - x ^{2} + 3 )}{( x ^{2} + 1 ) ^{3}}

\frac{\partial}{\partial x} (A)

x \to 1 lim (\frac{ln ( x )}{x})

d er i v a t i v e - \frac{2}{x}

\int \frac{1}{x ^{2} ( x + 2 )} d x

d er i v a t i v e 3 x^{2} + 8 x + 2