Let f:R→R be an increasing function satisfying the following conditions:
1. f(x+1)=f(x)+1 for each x∈R,
2. there exists an integer p such that f(f(f(O)))=p. Prove that for every real number xn→∞limnxn=3p.
where x1=x and xn=f(xn−1) for n=2,3,….