Proving the Existence of a Fixed Point using the Intermediate Value Theorem

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Homework Help Overview

The discussion revolves around proving the existence of a fixed point for a continuous function defined on the interval [0, 1], specifically using the Intermediate Value Theorem (IVT). The original poster attempts to find a simpler proof than the one they have already provided, which involves constructing a new function.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the validity and simplicity of the proof involving the function g(x) = f(x) - x. Questions arise regarding the commonality of this proof in educational contexts and the existence of alternative, more complex proofs.

Discussion Status

The conversation indicates that while the original poster seeks a simpler proof, some participants affirm the existing proof's status as a standard example in teaching IVT. There is acknowledgment of other, more complicated proofs, suggesting a range of perspectives on the topic.

Contextual Notes

Participants reference the Intermediate Value Theorem and its applications, as well as the potential complexity of alternative proofs like Brouwer's fixed point theorem. The discussion reflects a mix of familiarity with the topic and a desire for clarity on proof methods.

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Homework Statement


Let f : [0; 1] -> [0; 1] be continuous on [0; 1]. Prove that there exists C \epsilon [0; 1] such
that f(c) = c.

Homework Equations


The Attempt at a Solution



I've manage to prove this by having an extra cont. function g(x)=f(x)-x .. But I am looking for easier proof
 
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Sorry, that's the easiest proof available :smile:
 
micromass said:
Sorry, that's the easiest proof available :smile:

Is it one of the common proof and example when they conduct lesson on IVT?
 
Yes, this is one of the common examples when discussing the IVT. There are other proofs however, but these are quite complicated (see Brouwers fixed point theorem)
 
Thank you! Greatly appreciate ur time =D
 

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