Question

What is f'(X) on the equation ?

Answer 1

`f(x) = cos^(4) (4 - 3x)`

(derivative of cos(x) is -sin(x))


`f(x) = (cos(4-3x))^(4)` [cos²x is same as (cosx)²]

f'(x) = 4(cos(4-3x))³ (-sin(4-3x)) (-3)
f'(x) = -12 (cos(4-3x))³(-sin(4-3x))
f'(x) = 12 cos³(4-3x) sin(4-3x)

Thus, c is the correct answer.