Is the set of even functions in C([-1,1],R) closed and dense in C([-1,1],R)?

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Homework Help Overview

The discussion revolves around the properties of the set of even functions within the space of continuous functions defined on the interval [-1, 1]. Participants are examining whether this set is closed and dense in the larger space of continuous functions.

Discussion Character

  • Conceptual clarification, Assumption checking, Mixed

Approaches and Questions Raised

  • Some participants question the definition of even functions in the context of the specified interval, particularly regarding the implications of the function being defined on [-1, 1]. Others explore the convergence of even functions and whether this leads to a valid conclusion about the properties of the set.

Discussion Status

The discussion is ongoing, with participants clarifying definitions and assumptions. There is a mix of confusion and attempts to explore the implications of the problem, particularly after a correction regarding the interval of consideration. Some guidance has been provided regarding the convergence of sequences of even functions.

Contextual Notes

There was initial confusion regarding the interval of the functions, with some posts referencing [0, 1] instead of the correct interval [-1, 1]. This has led to discussions about the meaning of even functions in this context.

benjamin111
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Homework Statement


Let Ce([0,1], R) be the set of even functions in C([0,1], R), show that Ce is closed and not dense in C.


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The Attempt at a Solution



I think I can solve this if I can show that even functions converge to even functions, but I can't quite figure out how to go about doing this...
 
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This question does not make sense to me.

A function is "even" is f(t)=f(-t). Here, for any t in (0,1], -t is out of [0,1] and thus f(-t) is not even defined.

What do you mean by even?
 
What does C([0,1],R) mean?
 
That would be the space of continuous functions on [0,1] no doubt.

But do you see what it means for a fct to be even in this setting? :confused:
 
I was wondering if it could mean continuous functions from [0,1]xR->R with 'even' meaning f(x,y)=f(x,-y). The failure of the question to make any obvious sense otherwise was giving me doubts.
 
I'm sorry all. I meant that the space is [-1,1] rather than [0,1]. Sorry again and do appreciate any help.
 
benjamin111 said:
I'm sorry all. I meant that the space is [-1,1] rather than [0,1]. Sorry again and do appreciate any help.

Then it's super easy. Take a sequence of even functions f_i converging to a function f. Take any point x, then f_i(x)->f(x) and f_i(-x)->f(-x). Need I say more?
 

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