JEE Main20231 Feb 2023Evening ShiftMathematicsFunctionsActual
Let f : R - 0 , 1 → R be a function such that f x + f 1 1 - x = 1 + x . Then f 2 is equal to :
Options
- A9 2
- B9 4
- C7 4
- D7 3
Correct answer
B. 9 4
Step-by-step solution
Given, f x + f 1 1 - x = 1 + x x = 2 ⇒ f 2 + f - 1 = 3                   … 1 x = - 1 ⇒ f - 1 + f 1 2 = 0         … 2 x = 1 2 ⇒ f 1 2 + f 2 = 3 2           … 3 On subtracting equation 3 and equation 2 we get, f ( 2 ) - f ( - 1 ) = 3 4   . . . . . . . . ( 4 ) On adding equation 1 and equation 4 we get, 2 f 2 = 9 2 ⇒   f 2 = 9 4