Discontinuous composite of continuous functions

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SUMMARY

The discussion centers on the challenge of finding continuous functions f and g at x=0, such that their composite f(g(x)) is discontinuous at the same point. A common example provided is f(x) = 1/x for x ≠ 0 and f(0) = 0, and g(x) = x^2, which is continuous at x=0. This example demonstrates that the continuity of individual functions does not guarantee the continuity of their composite. The conclusion drawn is that this scenario does not contradict the sandwich theorem, as the theorem applies to limits rather than direct function composition.

PREREQUISITES
  • Understanding of continuity in functions
  • Familiarity with the sandwich theorem
  • Basic knowledge of function composition
  • Experience with limits and discontinuities
NEXT STEPS
  • Study examples of continuous functions that yield discontinuous composites
  • Learn about the sandwich theorem and its applications in calculus
  • Explore the concept of limits and their role in function continuity
  • Investigate other theorems related to function composition and continuity
USEFUL FOR

Students studying calculus, particularly those grappling with concepts of continuity and function composition, as well as educators seeking examples to illustrate these principles.

M Dhanota
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Homework Statement



give an example of functions f and g, both continuous at x=0, for which the composite f(g(x)) is discontinuous at x=0. Does this contradict the sandwich theorem? Give reasons for your answer.

Homework Equations





The Attempt at a Solution


I understand the sandwich theorem, but I don't understand how I can just make up these functions! :confused:
 
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If f(g(x)) is discontinuous, what can we say about f(x) or g(x)?
 
I really want to say that one of the functions, either f(x) or G(x) is also discontinuous at a certain point. But not at x=0.
 

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