How Do Derivatives Relate to Uniform Continuity in Calculus?

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Homework Help Overview

The discussion revolves around the relationship between derivatives and uniform continuity in calculus, specifically examining differentiable functions and their properties. The original poster presents a problem involving inequalities between two functions and their derivatives, along with questions about uniform continuity based on the behavior of derivatives.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to formulate inequalities related to the functions f and g, expressing uncertainty about the approach. Some participants suggest considering the function f-g and its properties, while others inquire about additional hints to clarify the reasoning.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the use of the Mean Value Theorem and the implications of the derivative conditions, but there is no explicit consensus on the solution yet.

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information they can share or the methods they can use. The original poster's request for help indicates a need for clarification on the inequalities and their implications.

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Homework Statement


Suppose f and g are differentiable on R, and f(a) = g(a) and f'(x) <= g'(x) for all x >= a. Show that f(x) <= g(x) for all x >= a. Give a physical interpretation of this result.

Also, using the Mean Value Theorem:
(a) Let f: R --> R be a differentiable function. Suppose that its derivative f'(x) is bounded Prove that f is uniformly continuous.
(b) Let f: R --> R be a differentiable function. Suppose that lim (x --> infinity) f'(x) = infinity. Show that f cannot be uniformly continuous.
(c) Let g(x) = (x)^1/2 show that g'(x) is unbounded on (0,1] but g(x) is uniformly continuous on [0,1].

Homework Equations





The Attempt at a Solution


I don't know how to quite formulate the inequalities, any help?
 
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Consider the function f-g.
 
i still don't see it, any more hints? thanks
 
(f-g)(a) = 0, (f-g)'(x) < 0 for all x > a. Use MVT to prove that (f-g)(x) < 0 for all x > a.
 

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