derivative of cos^3(3x)

解答

\frac{d}{d x} (cos^{3} (3 x))

- 9 cos^{2} (3 x) sin (3 x)

求解步骤

\frac{d}{d x} (cos^{3} (3 x))

使用连锁律:

3 (cos (3 x))^{2} \frac{d}{d x} (cos (3 x))

= 3 (cos (3 x))^{2} \frac{d}{d x} (cos (3 x))

\frac{d}{d x} (cos (3 x)) = - sin (3 x) \cdot 3

= 3 (cos (3 x))^{2} (- sin (3 x) \cdot 3)

化简

= - 9 cos^{2} (3 x) sin (3 x)

f (x) = 3 x + 7

d er i v a t i v e y = 3^{x - 1}

f (x) = \frac{x}{x ^{2} + 9}

y^{^{''}} - 2 y^{^{'}} + 2 y = x + e^{x}

x \to 0 lim (- 5^{2})