JEE Main20236 Apr 2023Evening ShiftMathematicsFunctionsActual
Let the sets A and B denote the domain and range respectively of the function f x = 1 x - x , where x denotes the smallest integer greater than or equal to x . Then among the statements S 1 : A ∩ B = 1 , ∞ - ℕ and S 2 : A ∪ B = 1 , ∞
Options
- AOnly ( S 2 ) is true
- BOnly ( S 1 ) is true
- CNeither S 1 nor S 2 is true
- DBoth S 1 and S 2 are true
Correct answer
C. Neither S 1 nor S 2 is true
Step-by-step solution
Given, f x = 1 x - x We know that, x = x + x where x is fractional part of x whose value is 0 < x < 1 , So, x - x = - x Now putting the value in given function we get, f x = 1 x - x ⇒ f x = 1 - x Now we know that 1 g x is defined when g x > 0 , but - x ∈ - 1 , 0 Hence, - x is not defined Hence, Domain and Range will be = ϕ