AP EAMCET201920 Apr 2019Evening ShiftMathematicsFunctionsActual
If f: R- 3 7 R- 3 7 is given by f(x)= 3 x+5 7 x-3 , then the statement which is not true, is
Options
- Af⁻¹(x)=f(x)
- B(f f)(x)=x
- C(f f f)(x)=x
- D(f f f f)(x)=x
Correct answer
C. (f f f)(x)=x
Step-by-step solution
Given, function f: R- 3 7 R- 3 7 is define by f(x)= 3 x+5 7 x-3 . Let f(x)=y 3 x+5 7 x-3 =y x= 3 y+5 7 y-3 , so f(x) is a bijective function and f⁻¹(x)=f(x) . (f f)(x)=x and (f f f f)(x)=x But (f f f)(x) x . Hence, option (c) is correct.