derivative of-21x^2-3x_{+}8

解答

\frac{d}{d x} (- 21 x^{2} - 3 x_{+} 8)

- 42 x

求解步骤

\frac{d}{d x} (- 21 x^{2} - 3 x_{+} \cdot 8)

化简

- 21 x^{2} - 3 x_{+} \cdot 8 : - 21 x^{2} - 24 x_{+}

= \frac{d}{d x} (- 21 x^{2} - 24 x_{+})

将

x_{+}

视为常数

使用微分加减法定则:

(f \pm g)^{'} = f^{'} \pm g^{'}

= - \frac{d}{d x} (21 x^{2}) - \frac{d}{d x} (24 x_{+})

\frac{d}{d x} (21 x^{2}) = 42 x

\frac{d}{d x} (24 x_{+}) = 0

= - 42 x - 0

化简

= - 42 x

e x t re m e f (x) = 3 x - 6 cos (x), - 2 \leq x \leq 0

e x t re m e f (x) = \frac{3 x ^{2} - 8 x + 4}{x ^{2}}

e x t re m e f (x) = - 3 x^{2} + 30 x - 4

e x t re m e \frac{9 e ^{x}}{1 + e ^{- x}}

e x t re m e f (x) = 81 x - 3 x^{3}