Answer:
option B
Step-by-step explanation:
to find the pair whose (f o g) (x) = x
so,
(f o g) (x) means f (g(x)) means inserting value of g(x) in function f(x)
a) (f o g )(x) = f(g(x)) = [tex]f(\dfrac{1}{x}) = \dfrac{1}{x^2}[/tex]
b) (f o g )(x) = f(g(x)) = [tex]f(\dfrac{2}{x}) = \dfrac{2}{\dfrac{2}{x}}[/tex]
= x
hence, the correct answer is option B
