Most Important Selected Qs for JEE AdvancedMathematicsFunctions
Let a function f(x), x 0 be such that f(x)+f ( 1 x )=f(x) f ( 1 x ) then f(x) can be :
Options
- A1-x²⁰¹³
- B|x| +1
- C2 ⁻¹|x|
- D2 1+ k | x | , k being arbitrary constant
Correct answer
D. 2 1+ k | x | , k being arbitrary constant
Step-by-step solution
A & B are obvious aligned & ( f ( 1 x )-1 )= 1 ( f ( x )-1) i.e., ( f ( 1 x )-1 ) isreciprocal of ( f ( x )-1) & Now, forf f ( x )= / 2 ⁻¹| x | , f ( x )-1= ⁻¹| x | ⁻¹| x | , f ( 1 x )-1= ⁻¹| x | ⁻¹| x | & Alsofor f ( x )= 2 1+ k n | x | , f ( x )-1= 1- k n | x | 1+ k n | x | f ( 1 x )-1= 1+ k n | x | 1- k n | x | aligned