JEE Main2015MathematicsDefinite IntegrationActual
Let f : ( - 1 , 1 ) → R be a continuous function. If ∫ 0 sin ⁡ x f ( t ) d t = 3 2 x , then f 3 2 is equal to:
Options
- A3 2
- B3
- C1 2
- D3 2
Correct answer
B. 3
Step-by-step solution
∫ 0 s i n x f t d t =   3 2   x . Differentiating w.r.t x both the sides, f sin ⁡ x · cos ⁡ x =   3 2 Put x =   π   3 . 1 2 · f   3 2 = 3 2 f 3 2 = 3 .