NTA Abhyas JEE Main2020MathematicsIndefinite IntegrationPractice
If ∫ f x d x = 3 f x 2 + c (where c is the constant of integration) and f 1 = 1 6 , then f 6 π is equal to
Options
- Aπ 2
- Bπ
- Cπ 3
- Dπ 6
Correct answer
B. π
Step-by-step solution
Differentiating the given integral with respect to ‘ x ’ , we get, f x = 6 f x ⋅ f ′ x or 1 6 = f ′ x On integrating, we get, ∫ 1 6 d x = ∫ f ′ x d x ⇒ x 6 = f x + c As f 1 = 1 6 ⇒ c = 0 ⇒ f x = x 6 ⇒ f 6 π = π