The interval where the function $f(x)=2x^3-9x^2+12x+15$ is decreasing, is :
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → [1, 2]
$y=2x^3-9x^2+12x+15$
$\frac{dy}{dx}=6x^2-18x+12=0⇒x^2-3x+2=0$
$⇒(x-2)(x-1)=0$
so $x=1,2$
using wavy curve method
f(x) is decreasing in [1, 2]