derivative f(x)=(x^2-99)/(x-10)

解

導関数

f (x) = \frac{x ^{2} - 99}{x - 10}

\frac{x ^{2} - 20 x + 99}{( x - 10 ) ^{2}}

解答ステップ

\frac{d}{d x} (\frac{x ^{2} - 99}{x - 10})

商の法則を適用:

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

= \frac{\frac{d}{d x} ( x ^{2} - 99 ) ( x - 10 ) - \frac{d}{d x} ( x - 10 ) ( x ^{2} - 99 )}{( x - 10 ) ^{2}}

\frac{d}{d x} (x^{2} - 99) = 2 x

\frac{d}{d x} (x - 10) = 1

= \frac{2 x ( x - 10 ) - 1 \cdot ( x ^{2} - 99 )}{( x - 10 ) ^{2}}

簡素化

\frac{2 x ( x - 10 ) - 1 \cdot ( x ^{2} - 99 )}{( x - 10 ) ^{2}} : \frac{x ^{2} - 20 x + 99}{( x - 10 ) ^{2}}

= \frac{x ^{2} - 20 x + 99}{( x - 10 ) ^{2}}