# Unbounded sequence

## Homework Statement

show that the following sequence is unbounded

{xn}= [(n+1)/n]^3 - n^3

## The Attempt at a Solution

I expanded it but didnt get anywhere after that. I know that a sequence is unbounded if for all M>0 there exists N such that abs(xN)>M but i still dont understand how to show it.

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Tom Mattson
Staff Emeritus