If $$If (f \circ g \circ f)(x)=x, \forall x \epsilon \mathbb{R}$$ then show that $$(f \circ g)(x)=( g \circ f)(x)$$
$$If (f \circ g \circ f)(x)=x, \forall x \epsilon \mathbb{R}$$ then show that $$(f \circ g)(x)=( g \circ f)(x)$$