Can δ-ε Definitions Prove This Infinite Limit Scenario?

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SUMMARY

The discussion centers on proving the limit scenario using the δ-ε definition of limits. Specifically, it asserts that if lim (x→∞) g(x) = ∞ and g(x) ≤ f(x) as x approaches a, then it follows that lim (x→a) f(x) = ∞. Participants emphasize the importance of starting with the δ-ε definition to construct a formal proof and clarify the correct limit notation, highlighting the need for precision in mathematical expressions.

PREREQUISITES
  • Understanding of δ-ε definitions in calculus
  • Familiarity with limit notation and properties
  • Knowledge of inequalities in mathematical proofs
  • Basic skills in constructing formal mathematical arguments
NEXT STEPS
  • Study the δ-ε definition of limits in detail
  • Review examples of limit proofs involving inequalities
  • Practice constructing formal proofs in calculus
  • Explore advanced limit concepts, such as one-sided limits and their implications
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Students of calculus, mathematics educators, and anyone interested in mastering limit proofs and formal mathematical definitions.

Jimbo57
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Homework Statement



Prove, using the formal definition of limits:

If lim (x->inf) g(x) = inf and g(x) leq f(x) for x->a, then lim (x->a) f(x)=inf.

leq = less than or equal to.

Homework Equations


The Attempt at a Solution



Honestly, I'm not even sure where to start on this one. Anyone bored enough to show how they would solve it?
 
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Start with the δ-ε definition of a limit.

Show some work so we can help you. That's a rule for this Forum.

BTW: Don't you mean lim (x → a) g(x) = ∞ , NOT lim (x → ∞) ?
 

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