What is the Limit of a Sequence with L > 1?

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Homework Help Overview

The discussion revolves around the limit of a sequence where the limit L is greater than 1. Participants are exploring different approaches to demonstrate or prove the behavior of the sequence as it approaches infinity.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the possibility of using a comparison test or an ε-N proof. There are differing opinions on the complexity of the proof required, with some suggesting a rough demonstration while others advocate for a more rigorous approach. The sequence's behavior is analyzed through its ratio and limits, with questions about the implications of L being greater than 1.

Discussion Status

The discussion is active, with participants sharing their thoughts on the proof methods and the implications of the limit. Some have offered insights into the sequence's behavior, while others are questioning assumptions and exploring different interpretations of the problem.

Contextual Notes

There is a mention of a book that provides a proof for when L is less than 1, which contrasts with the current scenario of L being greater than 1. This highlights the need for clarity on the conditions under which the proofs apply.

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I doubt that he wants an ε - N proof.

Probably wants more than a rough demonstrative "proof". I would.

Do a comparison test. The hint is right there !
 
SammyS said:
I doubt that he wants an ε - N proof.

Probably wants more than a rough demonstrative "proof". I would.

Do a comparison test. The hint is right there !

Oh, I know. I just thought that was too easy. I'll work it out shortly.
 
xn = (sn)

sn+1/sn = xn+1/xn = x*xn/xn = x

x ≥ L > 1

Eh. I think that "proves" it. Assuming x > 1, then the sequence ratio is bigger than 1. And, of course, the limit is given which is infinity which is what we were asked to show for a sequence that satisfies that ratio.
 
Last edited:
Shackleford said:
xn = (sn)

sn+1/sn = xn+1/xn = x*xn/xn = x

x ≥ L > 1

Eh. I think that "proves" it. Assuming x > 1, then the sequence ratio is bigger than 1. And, of course, the limit is given which is infinity which is what we were asked to show for a sequence that satisfies that ratio.
I It doesn't say xn = (sn) at all.

sn+1 ≥ L sn ≥ L2 sn-1 ≥ L3 sn-2 ≥ ...

What can you say about \displaystyle \lim_{n\to\infty}L^n\,?

This leads nicely to an ε - N proof. Maybe do one.
 
SammyS said:
I It doesn't say xn = (sn) at all.

sn+1 ≥ L sn ≥ L2 sn-1 ≥ L3 sn-2 ≥ ...

What can you say about \displaystyle \lim_{n\to\infty}L^n\,?

This leads nicely to an ε - N proof. Maybe do one.

That limit should go to infinity, right?

The book does the proof for when L < 1. I'm looking over that proof now.
 
Last edited:
Shackleford said:
That limit should go to zero, right?

The book does the proof for when L < 1. I'm looking over that proof now.

No, it doesn't go to zero. L > 1 !
 
SammyS said:
No, it doesn't go to zero. L > 1 !

Yeah, I didn't mean to put zero.
 

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