Question

Let $f\left(x\right)=[2x^3-6]$ when $\left[x\right]$ is greatest integer less than or equal to $x$ then the number of points in (1,2) where $f$ is discontinuous is

• A. 5
• B. 7
• C. 13
• D. 2

Answer 1

Answer: (C)

13

$f\left(x\right)=-4$ when $x=1$
$f\left(x\right)=10$ when $x=2$
So, it is step function so it will be discontinous at
integer point so, it will be discontinous at
-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9