JEE Main202325 Jan 2023Morning ShiftMathematicsDefinite IntegrationActual
The minimum value of the function f x = ∫ 0 2 e x - t d t is
Options
- A2 e - 1
- B2 e - 1
- C2
- De e - 1
Correct answer
A. 2 e - 1
Step-by-step solution
Given, f x = ∫ 0 2 e x - t d t Now For x ≤ 0 f x = ∫ 0 2 e t - x d t = e - x e 2 - 1 And for 0 < x < 2 f x = ∫ 0 x e x - t d t + ∫ x 2 e t - x d t = e x + e 2 - x - 2 For x ≥ 2 f x = ∫ 0 2 e x - t d t = e x - 2 e 2 - 1 Now for x ≤ 0 ,   f x is decreasing as e - x is decreasing function and x ≥ 2 ,   f x is increasing as e x - 2 is increasing function, So, minimum value of f x lies in x ∈ 0 , 2 Applying A.M ≥ G.M in e x + e 2 - x we