Let f:R→R satisfy

f(a)≠0 for some a in R

f(xf(y))=yf(x) for all x,y in R
Prove that f(x)=f(x) for all x in R.
(In reply to
Please define y by Diane)
I think y is independent in condition 2. Thus, for whatever real numbers you choose for x and y, condition 2 holds.

Posted by Gamer
on 20061229 23:15:06 