Proving a Limit: Epsilon & Delta Solution

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Homework Help Overview

The discussion revolves around proving a limit using the epsilon-delta definition, specifically for the limit as x approaches 5 of a rational function. The original poster expresses uncertainty about handling the fraction in the limit proof and seeks guidance on how to manage the numerator and denominator effectively.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need to bound the numerator and denominator separately and explore the implications of restricting x to a specific interval. They raise questions about how to derive expressions for |f(x) - L| and how to ensure the conditions for epsilon and delta are met.

Discussion Status

Some participants suggest methods for bounding the function and highlight the importance of choosing appropriate delta values. There is an ongoing exploration of how to prove the limit and what steps are necessary to demonstrate the relationship between |x-5| and |f(x) + 3|. Multiple interpretations of the approach are being considered, and no consensus has been reached yet.

Contextual Notes

Participants note the need to avoid values that make the denominator zero and discuss the implications of their chosen intervals on the proof. There is also mention of the original poster's confusion regarding the notation and the steps involved in the epsilon-delta proof.

  • #31
learningphysics said:
|(x^2+2x+1)/(x^2-8x+14)| is bounded above by 42.25/1.75 over the range of |x-5|<1/2. If we didn't know that |x-5|<1/2, we wouldn't be able to use this bound.

Thanks. you're welcome. I really appreciate the compliment. :smile: But don't take my word for anything, or anyone else... convince yourself... it's possible I made a mistake. anyway, good luck on your exam!

Oh I understand now. I guess i completely forgot that we had to restrict x to the 1/2 interval. It makes complete sense now. I really appreciate you help and thanks :smile:

P.S. Wish you were my Professor, then life would be so much simplier
 

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