NTA Abhyas JEE Main2020MathematicsDefinite IntegrationPractice
Consider the definite integrals A = ∫ 0 π x sin x cos 2 x d x and B = ∫ 0 π 2 sin x cos 2 x d x . Then,
Options
- AA = 2 B
- BA = π B
- CA = π 2 B
- DB = 2 A
Correct answer
B. A = π B
Step-by-step solution
Applying a + b - x property in A , and adding, we get, 2 A = ∫ 0 π x + π - x sin x cos 2 x d x ⇒ 2 A = π ∫ 0 π sin x cos 2 x d x ∴ 2 A = π ⋅ 2 ∫ 0 π 2 sin x cos 2 x d x ⇒ A = π B