If f(x) =x+2 and f(x) ^\circ f(x) ^\circ f(x) ^\circ...=q where ^\circ represents the composition of two function and n denotes the number of times of composition, the value of n is given by which of the following expressions.?
If [math]x+y=1[/math], what is the value of [math]x-y[/math]?