\fStep 1: Prove that 2n (4) 71 2 + 1 -0 0, we have 2/= ( R and 2/= > 0. By a well-known property (can you identify it?), there exists a K ( N such that K > 2/E. When n > K, one has n > 2/6 > 0, which implies that 1 (5) - (2/E) Vn 2 K. What do you get when n 2 K if you combine (4) and (5)? What can you then 2n conclude about the sequence n2+ 1