Squeeze Theorem for derivatives

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SUMMARY

The discussion centers on the Squeeze Theorem for derivatives, specifically addressing the conditions under which the inequalities g(x) < f(x) < h(x) and the derivatives derivative(g(x0)) = derivative(h(x0)) = m do not guarantee that derivative(f(x0)) = m or even that it exists. Participants emphasize the need for additional conditions beyond the inequalities to establish the derivative of f at x0. The conversation highlights the necessity of formal proofs in calculus, particularly when dealing with derivatives and their limits.

PREREQUISITES
  • Understanding of the Squeeze Theorem in calculus
  • Familiarity with the definition of derivatives, specifically derivative(g(x)) = lim(h tends to zero) (g(x+h)-g(x))/h
  • Knowledge of continuity and differentiability of functions
  • Ability to construct formal mathematical proofs
NEXT STEPS
  • Research the implications of the Squeeze Theorem on differentiability
  • Study examples of functions that demonstrate the failure of derivative(f(x0)) = m under the given conditions
  • Explore additional conditions that can be applied to g, f, and h to ensure derivative(f(x0)) exists
  • Learn about formal proof techniques in calculus, particularly in relation to limits and derivatives
USEFUL FOR

Students studying calculus, particularly those focusing on derivatives and the Squeeze Theorem, as well as educators seeking to clarify the nuances of differentiability conditions.

benf.stokes
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Homework Statement



Show, with appropriate examples, that the conditions g(x) < f(x) < h(x) and derivative(g(x0))=derivative(h(x0)) = m does not imply derivative(f(x0)) = m or even exists. And with some additional condition.

Homework Equations



derivative g(x) = lim(h tends to zero) (g(x+h)-g(x))/h

The Attempt at a Solution



How do I even get started?
Thanks
 
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Start by identifying the simplest function you can think of which has no derivative at, say, x = 0.

By the way, the problem seems almost too simple as stated. But what do you mean "and some additional condition"? Are there some more constraints on g, f, and/or h? E.g., do their values have to be close to each other at [itex]x_0[/itex]?
 
Thanks for the reply. The problem does require a formal proof although I know it may not appear because of my sloppy translation.
And the aditional conditional means that something other than g < f < h is required for deriv g < deriv f = deriv h = m
 

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