NTA Abhyas JEE Main2020MathematicsIndefinite IntegrationPractice
If the integral Ι = ∫ e x 2 x 3 d x = e x 2 f x + c , where c is the constant of integration and f 1 = 0 , then the value of f 2 is equal to
Options
- A4
- B5 2
- C3 2
- D3
Correct answer
C. 3 2
Step-by-step solution
Let, x 2 = t ⇒ 2 x d x = d t ∴ Ι = ∫ e t ⋅ t 2 d t Using integration by parts, we get, Ι = 1 2 t e t - ∫ 1 ⋅ e t d t = 1 2 t e t - e t + c = e x 2 x 2 - 1 2 + c ∴ f x = x 2 - 1 2 ⇒ f 2 = 3 2