Interval in which the function $f(x) =2x^3-3x^2-12x+10 $ is decreasing is :
Answer & explanation
Correct answer: option 3
The correct answer is option (3) → $[-1, 2]$
$f(x) =2x^3-3x^2-12x+10$
$f'(x) =6x^2-6x-12=0$
$x^2-x-2=0$
$(x-2)(x+1)=0⇒x=-1,2$
wavy curve method
f is decreasing in [-1, 2]