Question related to inequalities and limits that go to infinity

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Discussion Overview

The discussion revolves around the relationship between two functions, f(x) and g(x), particularly focusing on the implications of the inequality f(x) > g(x) for all x and the limit behavior of g(x) as x approaches infinity. Participants explore whether this leads to a conclusion about the limit of f(x) as x approaches infinity, considering the appropriate mathematical theorems to reference.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant proposes that if f(x) > g(x) for all x and the limit of g(x) as x approaches infinity is infinity, then the limit of f(x) as x approaches infinity should also be infinity.
  • Another participant suggests considering the Squeeze Theorem in this context.
  • A different participant expresses doubt about the applicability of the Squeeze Theorem, noting that f(x) is not "squeezed" between two functions.
  • One participant elaborates on the meaning of the limit of g(x) approaching infinity, indicating that for any real number Y, there exists an X such that g(x) exceeds Y for all x greater than X, and suggests applying this fact in conjunction with the inequality f(x) > g(x).

Areas of Agreement / Disagreement

Participants do not reach a consensus on the applicability of the Squeeze Theorem, with differing views on whether it is relevant to the problem at hand. The discussion remains unresolved regarding the best approach to demonstrate the limit behavior of f(x).

Contextual Notes

There are limitations regarding the assumptions made about the functions f(x) and g(x), particularly concerning their behavior as x approaches infinity and the definitions of the limits involved.

eggmanneo
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I want to show that if [itex]f(x) > g(x)[/itex] [itex]\forall x \in (-\infty, \infty)[/itex] and [itex]\displaystyle\lim_{x\to\infty}g(x)=\infty[/itex], then [itex]\displaystyle \lim_{x\to\infty}f(x)=\infty[/itex]. This result is true, correct? If so, what theorem should I use or reference to show this result? I wasn't sure if the squeeze theorem was application to this problem.
 
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Have you considered the Squeeze Theorem?
 
I may be entirely incorrect, but I don't think the squeeze theorem would be very helpful. f(x) isn't "squeezed" between two functions.
 
Consider what it means for ##\lim_{x \rightarrow \infty} g(x) = \infty## to be true. Given any ##Y \in \mathbb{R}##, there is some ##X \in \mathbb{R}## such that ##g(x) > Y## for all ##x > X##. Now apply the fact that ##f(x) > g(x)##.
 

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