JEE Main202126 Feb 2021Morning ShiftMathematicsDefinite IntegrationActual
The value of ∑ n = 1 100 ∫ n - 1 n e x - x d x , where x is the greatest integer ≤ x , is:
Options
- A100 e - 1
- B100 e
- C100 1 - e
- D100 1 + e
Correct answer
A. 100 e - 1
Step-by-step solution
∑ n = 1 100 ∫ n - 1 n e x d x , period of x = 1 ∑ n = 1 100 ∫ 0 1 e x d x = ∑ n = 1 100 ∫ 0 1 e x d x ∑ n = 1 100 e - 1 = 100 e - 1