JEE Main202120 Jul 2021Evening ShiftMathematicsDefinite IntegrationActual
If [ x ] denotes the greatest integer less than or equal to x , then the value of the integral ∫ - π / 2 π / 2 x - sin x d x is equal to:
Options
- A- π
- Bπ
- C0
- D1
Correct answer
A. - π
Step-by-step solution
We have, I = ∫ - π / 2 π / 2 x - sin x d x   … i ⇒ I = ∫ - π 2 - 1 x - sin x d x + ∫ - 1 0 x - sin x d x + ∫ 0 1 x - sin x d x + ∫ 1 π 2 x - sin x d x ⇒ I = ∫ - π / 2 - 1 - 2 - sin x d x + ∫ - 1 0 - 1 - sin x d x + ∫ 0 1 0 - sin x d x + ∫ 1 π 2 1 - sin x d x ⇒ I = - 2 ∫ - π / 2 - 1 d x - ∫ - 1 0 d x - 1 ∫ 0 1 d x + ∫ 1 π 2 0 · d x ⇒ I = - 2 - 1 + π 2 - 1