Proving Negation of Limit Definition

antiemptyv
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Homework Statement



I'm trying to show that a sequence does not have a limit, so that would mean proving the negation of the limit definition is true, right? Is this a correct negation of the definition of what it means for a sequence to have a limit?

Homework Equations



The definition of the limit of a sequence (x_n).
The sequence (x_n) converges to L if given \epsilon > 0, \exists K(e) \in \mathbb{N} \ni if n > K(e), then |x_n-L| < \epsilon.

The Attempt at a Solution



The limit of a sequence (x_n) is not L if \exists \epsilon > 0 \ni \forall K \in \mathbb{N}, \existsn \in \mathbb{N} \ni n > K \ni |x_n - L| \geq \epsilon.
 
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I think that is right, except it seems as if you have used too many N's, \in's or \ni's.
 
antiemptyv said:

Homework Statement



I'm trying to show that a sequence does not have a limit, so that would mean proving the negation of the limit definition is true, right? Is this a correct negation of the definition of what it means for a sequence to have a limit?

Homework Equations



The definition of the limit of a sequence (x_n).
The sequence (x_n) converges to L if given \epsilon > 0, \exists K(e) \in \mathbb{N} \ni if n > K(e), then |x_n-L| < \epsilon.

The Attempt at a Solution



The limit of a sequence (x_n) is not L if \exists \epsilon > 0 \ni \forall K \in \mathbb{N}, \existsn \in \mathbb{N} \ni n > K \ni |x_n - L| \geq \epsilon.
Not if by "if n&gt; K(e)[/tex] then |x_n_L|&amp;lt; \epsilonyou mean &quot;for all n&gt; N(e).<br /> That only has to be true for <b>some</b> n&gt; Ke)
 
Yes, it all seems right now I guess. Thanks! and oh yeah, i guess while editting, i left in a few extra symbols...
 
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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