NTA Abhyas JEE Main2020MathematicsDefinite IntegrationPractice
Consider the integral I n = ∫ 0 π 4 sin 2 n − 1 x sin x d x , then the value of I 20 - I 19 is
Options
- A1 20
- B- 1 19
- C- 1 25
- D1 19
Correct answer
B. - 1 19
Step-by-step solution
I 20 − I 19 = ∫ 0 π 4 sin 39 x − sin 37 x sin   x d x ⇒ I 20 − I 19 = ∫ 0 π 4 2 sin   x   cos 38 x sin   x d x = sin 38 x 19 π 4 0 = sin 38 π 4 19 = - 1 19