Real Analysis: product of convergent sequences

uva123
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Homework Statement



suppose {an} and {bn} are sequences such that {an} converges to A where A does not equal zero and {(an)(bn)} converges. prove that {bn} converges.


Homework Equations



What i have so far:
(Note:let E be epsilon)
i know that if {an} converges to A and {bn}converges to B then {(an)(bn)} converges to AB.

Let {(an)(bn)}converge to a limit, call it L. E > 0 is given, there exists a positive integer N such that n>N implies
|(an)(bn) − L| < E


The Attempt at a Solution



how can i prove that if the product of two sequences is a convergent sequence, then the two multiplies sequences are also convergent? i think i need to prove this with a contradiction but i don't know why if {an} is convergent, {bn} can't be divergent...what does it mean if it is divergent?
please help any way you can!
 
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for proof by contradiction, start with the definition of convergence and take the logical NOT of the statement
 
Last edited:
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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