Inverse of a Function Proof Problem

[cyberspace]

Prove that:

f^-1(f(x))= x

here are the steps I did so far:
Let f(x)=y

f^-1(y)=x

f^-1(x)=y

...And I got stuck here. I don't have to name any proofs, I just need to make it so that f^-(f(x)) equals to x.

Thanks!

 

[skeeter]

Let f(x) = y. By definition of an inverse function, f[sup:2t5qxrf6]-1[/sup:2t5qxrf6](y) = x.

so ...

f[sup:2t5qxrf6]-1[/sup:2t5qxrf6][f(x)] = f[sup:2t5qxrf6]-1[/sup:2t5qxrf6](y) = x.

 

[cyberspace]

So I already have the answer?