Can Continuous Functions on [0,1] Approach 1 but Not Equal 1 at x=1?

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Discussion Overview

The discussion centers around the existence of continuous functions defined on the interval [0,1] that approach the value 1 as x approaches 1, but do not equal 1 at x=1. Participants explore the implications of continuity and the properties of the set of such functions.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant proposes the set D, defined as the set of continuous functions on [0,1] where f(1) does not equal 1, and questions whether a function can exist that approaches 1 without being equal to 1 at x=1.
  • Another participant suggests that to show D is not closed, one must find a sequence of functions in D that converges to a function not in D, providing an example function f_n(x) = n / (n + 1) that converges to f(x) = 1.
  • There is a clarification sought regarding the initial question about finding a specific function that meets the criteria of approaching 1 while not being equal to 1 at x=1.

Areas of Agreement / Disagreement

Participants generally agree on the approach to demonstrate that D is not closed by identifying a limit point outside of D. However, there is some confusion regarding the initial question about constructing a specific function that meets the criteria.

Contextual Notes

The discussion involves assumptions about the properties of continuous functions and the nature of limit points in the context of function spaces. The implications of continuity on the behavior of functions at boundary points are also considered.

Who May Find This Useful

This discussion may be of interest to those studying real analysis, particularly in understanding the properties of continuous functions and the concept of closed sets in function spaces.

Ed Quanta
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So if D={f is an element of C[0,1];f(1) does not equal 1}

and C[0,1] is the set of complex valued continuous functions on the interval [0,1], is there a function f such that f approaches 1 and f(1) does not equal 1?

I feel like there has to be one but I am unable to construct one since if the lim as x approaches 1 does not equal f(1)=1, then f wouldn't be continuous right?

I'm trying to show that D doesn't contain all of its limit points since that would be all that is required to show D is not closed.

Help with finding this function if there is one please.
 
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Ed Quanta said:
So if D={f is an element of C[0,1];f(1) does not equal 1}

and C[0,1] is the set of complex valued continuous functions on the interval [0,1], is there a function f such that f approaches 1 and f(1) does not equal 1?

I feel like there has to be one but I am unable to construct one since if the lim as x approaches 1 does not equal f(1)=1, then f wouldn't be continuous right?

I'm trying to show that D doesn't contain all of its limit points since that would be all that is required to show D is not closed.

Help with finding this function if there is one please.

I don't understand what you are looking for. If you're trying to show that D is not closed by finding a limit point outside of D, then all you have to do is find a sequence of functions in D that converges to a function not in D.

For example, take f_n(x) = n / (n + 1). Then every f_n is in D, but the sequence converges to f(x) = 1, which is not in D.
 
Yeah, you basically answered my question
 
Ed Quanta said:
Yeah, you basically answered my question

But then why were you asking about trying to find a function such that f(1) != 1 but f(x) -> 1 as x -> 1?
 

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