1. The problem statement, all variables and given/known data Prove that if (i) [tex]\forall n[/tex][tex]\in N[/tex], u - (1/n) is not an upper bound of s (ii) [tex]\forall n[/tex][tex]\in N[/tex], u + (1/n) is an upper bound of S then, u = supS 2. Relevant equations 3. The attempt at a solution It (i) and (ii) are true, then [tex]\exists s[/tex][tex]\in S[/tex] s.t. u - (1/n) < s and u+(1/n)>s for all s. I'm not sure where to go from here.