So the monotone convergence theorem states that if a sequence is bounded and monotone then it converges.
Now I am trying to prove that the sequence defined recursively as x1=√2, xn+1=√2xn converges and to find it's limit.
I am able to show that the sequence is monotone by determining if the ratio of xn+1xn is greater than and equal to or less than or equal to 1. I am even know what the limit is.
My dilemma is I am not sure how to determine if this sequence is bounded and I am not quite sure what I need to do to show that its bounded. Can anyone offer a few hints or strategies? I know that it is bounded below by √2; however the sequence is increasing so I need to show that there is an upperbound as well.
Answer
Hint: Use Induction. Suppose xn<2, what can you say about xn+1?
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