Convergence Induction for Positive Sequences: Proving Limit Behavior

mathmajo
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Homework Statement


If (an) — > 0 and \bn - b\ < an, then show that (bn) — > b


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The Attempt at a Solution

 
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Please show your attempt at the solution.
 
Since an --> 0, given some epsilon>0, there exists and m>0 such that /an-0/=/an/<epsilon for all n>m
thus, /bn-b/</an/<epsilon for all n>m
therefore, by definition bn-->b
 
mathmajo said:
Since an --> 0, given some epsilon>0, there exists and m>0 such that /an-0/=/an/<epsilon for all n>m
thus, /bn-b/</an/<epsilon for all n>m
therefore, by definition bn-->b

Looks ok to me.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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