Maximizing a Continuous Function on A: Analysis Homework Help

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Homework Help Overview

The problem involves finding a continuous function defined on the interval A = [0,1) that does not attain a maximum value. The original poster suggests functions such as g(x) = x or g(x) = e^x and is seeking guidance on how to formally demonstrate that these functions do not reach a maximum within the specified interval.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to identify properties of the suggested functions that would prevent them from attaining a maximum value. Participants question what specific property would indicate that a maximum cannot be reached and suggest considering the implications of assuming a maximum exists.

Discussion Status

Participants are engaged in exploring the properties of the proposed functions and discussing the necessary reasoning to show that a maximum is not attained. Some guidance has been offered regarding the need to analyze the implications of assuming a maximum exists, but no consensus or resolution has been reached yet.

Contextual Notes

The discussion is constrained by the requirement to provide information without fully revealing solutions, emphasizing the need for formal justification of the properties of the functions in question.

Janez25
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Homework Statement



Let A= [0,1). Find a continuous function g: from A to R that does not attain a maximum value.

Homework Equations





The Attempt at a Solution


I believe that g(x)=x or g(x)=e^x represent such a function, but I do not know how to use the IVT to prove that either of them work. Please help! I need as much information as possible without completely giving away the answer.
 
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Hi Janez25! Welcome to PF! :wink:
Janez25 said:
… I believe that g(x)=x or g(x)=e^x represent such a function, but I do not know how to use the IVT to prove that either of them work.

Yes, either will do :smile:

now, what property (of either) means that the maximum is never reached?

(i don't think you need the IVT for this)
 


I am not sure what property I should use. I also am not sure how to show that either function does not attain a maximum value on the interval [0,1) formally.
 
Janez25 said:
I am not sure what property I should use. I also am not sure how to show that either function does not attain a maximum value on the interval [0,1) formally.

Hint: asssume it does attain its maximum, or any local maximum, at x = a in [0,1) …

is that possible for x or for ex?

what property would f(x) have if that isn't possible?
 
Thanks for your help!
 

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