question 1 : Prove that a sequence which is bounded above cannot tend to infinity What i did was state the definition ... but I'm trying to proof by contradiction. So i first suppose that a(n) tends to infinity , then a(n) > C . But since it is bounded above , C < or = to U , where U is the upper bound . This is where i got stuck. Any ideas ? question 2 : I am required to prove the this sequence does not tend to infinity B(n) = cos(n^2 + 7) how am i suppose to do this ?