Function f(x) such that it's continuous

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    Continuous Function
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Discussion Overview

The discussion revolves around the concept of continuity and limits in the context of a function f(x). Participants explore the definitions and implications of limits, particularly focusing on the behavior of functions at specific points and the conditions under which limits can be evaluated. The scope includes theoretical aspects of limits, mathematical reasoning, and clarifications on continuity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant defines variables related to limits and continuity, suggesting that δ and ε are crucial for determining how close f(x) is to a limit l.
  • Another participant challenges the assumption that f(a) equals the limit l, using a piecewise function to illustrate a case where the limit does not equal the function value at that point.
  • A participant expresses confusion over the existence of two values of δ for different behaviors of the function on either side of a point, suggesting that this might necessitate two values of ε.
  • One reply asserts that the limit is 1 for the piecewise function discussed, providing a detailed argument and examples to support this claim.
  • Another participant reflects on their understanding of limits, questioning the necessity of considering both x - a and x + a in the context of limits and continuity.
  • There is a discussion about the relevance of the function's value at the point of interest (a) in determining the limit, with some participants noting that the limit can exist independently of the function's value at that point.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the evaluation of limits, particularly in the context of the piecewise function. There is no consensus on the correct limit value, as some argue for 1 while others suggest it could be 2. The discussion remains unresolved with competing views on the definitions and implications of limits and continuity.

Contextual Notes

Participants express uncertainty about the definitions and applications of δ and ε, as well as the implications of continuity for different types of functions. There are unresolved questions about the behavior of limits in piecewise functions and the conditions under which limits can be evaluated.

  • #31


LaTeX Code: \\lim_{x\\to a} f(x)= L
It means that the value of x reaches a, the value of f(x) also reaches L.

this is more like:

AS x APPROACHES a, f(x) APPROACHES L. If x reaches a, then f(x) is just f(a), but I'm pretty sure you have the idea, f(x) may not be able to reach f(a) - then the limit of that "approach" is L.
 
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  • #32


The distance form f(x) to L, f(x)- L (not f(x) alone), can be larger than \epsilon for some x, just not for x "sufficiently close" to a. Once x is within some distance of a, |f(x)- L| cannot exceed \epsilon. And that "distance" is, of course, \delta.

Yes, I was expecting this barrier...thanks for telling.

Close but not exactly. The value f(x) "reaches" when x reaches a is f(a). The question is what happens when x is close to a but not equal to a.

Yes, I'll modify that sentence accordingly.

It should be close.

Ok then, thanks everyone!
 

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