NTA Abhyas JEE Main2020MathematicsIndefinite IntegrationPractice
If ∫ d x e x - 1 = 2 t a n - 1 f x + C , (where x > 0 and C is the constant of integration) then the range of f x is
Options
- A0 , ∞
- B0 , ∞
- C1 , ∞
- D1 , ∞
Correct answer
A. 0 , ∞
Step-by-step solution
Le,t e x - 1 = t 2 ⇒ e x ⋅ d x = 2 t d t ∴ Ι = ∫ 2 t d t t e x = ∫ 2 d t t 2 + 1 = 2 t a n - 1 t + C = 2 t a n - 1 e x - 1 + C ∴ f x = e x - 1 For x ∈ 0 , ∞ ; e x ∈ 1 , ∞ ⇒ e x - 1 ∈ 0 , ∞