Absolute Value of Limits Proof

tnocel1
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Homework Statement



Show that if bn→b, then the sequence of absolute values |bn| converges to |b|.

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The Attempt at a Solution



I've been proving various properties of limits, including product of limits and sum of products, but have been having trouble making progress with the approach to absolute value of limits. I was also wondering is the converse of this is true, that is if |bn|→|b|, is it also true that (bn)→b
 
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Not at all, for example |(-1)^n| -> 1, but (-1)^n doesn't converge at all!
How about you start by writing down formally the assumption and what you want to prove. You will see that it's pretty straight forward then.
 
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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