you know that f is increasing where f' > 0
f' = -6x^2+12x+48 = -6(x^2-2x-8) = -6(x-4)(x+2)
So, now you know where f'=0
where is f' > 0 and f' < 0 ?
The function
f(x)=−2x^3+6x^2+48x−6
is increasing on the interval ( ).
It is decreasing on the interval ( −∞, ) and the interval ( , ∞ ).
The function has a local maximum at ( )
1 answer