f(x)=tan(x*pi/2)

Solving for y: x=tan(y*pi/2) then, y=2/p1*(arctan(x))

so, lets now let g(x)=2/p1*(arctan(x))

g(f(x))=g(tan(x*pi/2))=2/p1*(arctan(tan(x*pi/2))=x

f(g(x))=f(2/pi*(arctan(x))=tan((2/pi*arctan(x))*pi/2)=x

Sorry, the notation is messy. Basically I'm just trying to find the compositions of f(x) and g(x). So, g o f and f o g. I have gone blank on my trig and my calc is giving me all kinds of wierd results.

Thanks.