JEE Main2016MathematicsDefinite IntegrationActual
If 2 ∫ 0 1 tan - 1 x d x = ∫ 0 1 cot - 1 1 - x + x 2 d x , then ∫ 0 1 tan - 1 1 - x + x 2 d x is equal to
Options
- Aπ 2 + ln 2
- Bln 2
- Cπ 2 - ln 4
- Dln 4
Correct answer
B. ln 2
Step-by-step solution
From the given equation 2 ∫ 0 1 tan - 1 ⁡ x d x =   ∫ 0 1 π 2 - tan - 1 ⁡ 1 - x + x 2 d x ⇒ 2 ∫ 0 1 tan - 1 ⁡ x d x =   ∫ 0 1 π 2   d x -   ∫ 0 1 tan - 1 ⁡ 1 - x + x 2 d x ⇒ ∫ 0 1 tan - 1 ⁡ 1 - x + x 2 d x = π 2 - 2   ∫ 0 1 tan - 1 ⁡ x d x         … i Let I 1 =   ∫ 0 1 tan - 1 ⁡ x d x = tan - 1 ⁡ x x 0 1 - ∫ 0 1 1 1 + x 2 x d x =