I'm trying to answer questions regarding infima and suprema but I am not sure on how to answer this question. It goes like this:

Let { }. Prove that A is unbounded and that sup(A)=1.

I have rewritten this as:

{ }

So that the n-th term is

I am not sure if I needed to find the n-th term but I am not sure what I can do with this question?

EDIT I have solved this question now so no need for an answer. Thanks.