$\text { Find the derivative of the function } f ( x ) = - 4 x ^ { 2 } - 4 \cos ( x ) \text {. }$
A) $f ^ { t } ( x ) = - 4 x + 4 \sin ( x )$
B) $f ^ {t } ( x ) = - 8 x + 4 \sin ( x )$
C) $f ^ { t } ( x ) = - 8 x + 4 \cos ( x )$
D) $f ^ { t} ( x ) = - 8 x - 4 \sin ( x )$
E) $f ^ { t } ( x ) = - 8 x - 4 \cos ( x )$

Question

$\text { Find the derivative of the function } f ( x ) = - 4 x ^ { 2 } - 4 \cos ( x ) \text {. }$ 
A) $f ^ { t } ( x ) = - 4 x + 4 \sin ( x )$
B) $f ^ {t } ( x ) = - 8 x + 4 \sin ( x )$
C) $f ^ { t } ( x ) = - 8 x + 4 \cos ( x )$
D) $f ^ { t} ( x ) = - 8 x - 4 \sin ( x )$
E) $f ^ { t } ( x ) = - 8 x - 4 \cos ( x )$

Quizplus · Accepted Answer

The derivative of $f(x) = -4x^2 - 4\cos(x)$ is found by applying the power rule to $-4x^2$, giving $-8x$, and the derivative of $-4\cos(x)$, which is $4\sin(x)$, resulting in $f'(x) = -8x + 4\sin(x)$.

Find the derivative of the function f(x)=−4x2−4cos⁡(x). \text { Find the derivative of the function } f ( x ) = - 4 x ^ { 2 } - 4 \cos ( x ) \text {. } Find the derivative of the function f(x)=−4x2−4cos(x).

$\text { Find the derivative of the function } f ( x ) = - 4 x ^ { 2 } - 4 \cos ( x ) \text {. }$