The interval on which the function $f(x)=2x^3+12x^2+18x-7$ is decreasing, is :
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (-3, -1)
$f(x)=2x^3+12x^2+18x-7$
$f'(x)=6x^2+24x+18=0$
$x^2+4x+3=0$
$(x+3)(x+1)=0$
$⇒x=-3,-1$
Using wavy curve method
⇒ f is decreasing in (-3, -1)