NTA Abhyas JEE Main2020MathematicsContinuity and DifferentiabilityPractice
If f x = x x + x x + sin π x , where [·] and · represent the greatest integer function and the fractional part function respectively, then f ' 7 2 is equal to
Options
- A3 l n 3 + π 4
- B3 l n 3 + 3 π 4
- C3 l n 3 + π + 3 4
- D3 l n 3 + 3 4
Correct answer
D. 3 l n 3 + 3 4
Step-by-step solution
f x = x x + x x + sin ⁡ π x f x = 3 x - 3 + x - 3 3 + sin ⁡ π x , x ∈ 3 ,   4 f ' x = 3 x - 3 ln ⁡ 3 + 3 x - 3 2 + π cos ⁡ π x ∴   f ' 7 2 = 3 l n 3 + 3 4