NTA Abhyas JEE Main2020MathematicsDefinite IntegrationPractice
If A n = ∫ 0 n π sin x d x , ∀ n ∈ N , then ∑ r = 1 10 A r is equal to
Options
- A100
- B110
- C55
- D105
Correct answer
B. 110
Step-by-step solution
As the period of y = sin ⁡ x is π , hence A n = n ∫ 0 π sin ⁡ x d x = n ∫ 0 π sin ⁡ x d x = n - cos ⁡ x 0 π = 2 n ∴ ∑ r = 1 10 A r = ∑ r = 1 10 2 r = 2 1 + 2 + . . . . + 10 = 2 × 10 × 11 2 = 110