Limit with n tending to infinity

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    Infinity Limit
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Discussion Overview

The discussion revolves around the behavior of limits as \( n \) approaches infinity, particularly focusing on the asymptotic relationship between functions \( f(n) \) and \( g(n) \). Participants explore concepts related to asymptotic notation and the implications of such relationships in mathematical proofs, including a specific limit involving integrals and sums of powers.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that if \( \frac{f(n)}{g(n)} = 1 \) as \( n \to \infty \), then \( f(n) \) approaches \( g(n) \), suggesting that the functions diverge in a specific manner, exemplified by \( \pi(n) \sim \frac{n}{\ln(n)} \).
  • Others challenge the interpretation of asymptotic relationships, arguing that two asymptotic functions can diverge at different rates, questioning whether \( f - g \) tends to zero.
  • A participant recalls that \( \frac{f(n)}{g(n)} = 1 \) indicates \( f(n) \sim g(n) \), referencing asymptotic notation.
  • One participant introduces a separate question regarding the limit of the ratio of an integral to a sum of powers as \( n \) approaches infinity, seeking to prove the equality \( \frac{\int_0^{n} x^p \, dx}{1^p + 2^p + 3^p + \ldots + n^p} \to 1 \).
  • Another participant asserts that the limit tends to a constant for integer \( p \), suggesting that the sum of the first \( p \) powers is a polynomial of degree \( p+1 \) and encourages simplification of the integral.

Areas of Agreement / Disagreement

Participants express differing views on the implications of asymptotic relationships, with some asserting that \( f(n) \) and \( g(n) \) can diverge while remaining asymptotic, while others maintain a more traditional interpretation. The question regarding the limit involving integrals and sums remains open for further exploration.

Contextual Notes

Limitations include potential misunderstandings of asymptotic notation and the specific conditions under which the proposed limits hold. The discussion also reflects varying levels of familiarity with mathematical proofs and concepts.

eljose
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let,s suppose that we have the limit with n tending to infinity:
[tex]\frac{f(n)}{g(n)}=1[/tex] then i suppose that for n tending to infinity we should get:
[tex]f(n)\rightarrow{g(n)}[/tex] or what is the same the function f(n) diverges as g(n) as an special case:
[tex]\pi(n)\rightarrow{n/ln(n)}[/tex] where Pi is the prime number counting function in number theory
 
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eljose said:
let,s suppose that we have the limit with n tending to infinity:
[tex]\frac{f(n)}{g(n)}=1[/tex] then i suppose that for n tending to infinity we should get:
[tex]f(n)\rightarrow{g(n)}[/tex] or what is the same the function f(n) diverges as g(n) as an special case:
[tex]\pi(n)\rightarrow{n/ln(n)}[/tex] where Pi is the prime number counting function in number theory
What is your question? What you;'ve written doesn't make sense.

Are you attempting to ask: if f and g are asymptotic then does f-g tend to zero? Of course not: we can make two functions that are asymptotic diverge absolutely as fast as you want.
 
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As I recall, that [itex]\frac{f(n)}{g(n)}=1\mbox{ as }n\rightarrow\infty[/itex] speaks of the asymptotic relationship between f and g, namely that [itex]f(n) \sim g(n)[/itex] (ref. Asymptotic Notation).
 
My main question is related with proving (if true) the equality

[tex]\frac{\int_0^{n}dx(x^p)}{1^p+2^p+3^p+...+n^p}\rightarrow{1}[/tex]

as n tends to infinity [tex]n\rightarrow{\infty}[/tex]
 
It certainly tends to a constant (for p an integer), as anyone can tell you, since the sum of the first p powers is a poly of degre p+1. Surely you can actually solve it, it's straightforward (especially from someone who has solved the RH amongst other things that snobbish mathematicians wont' acknowledge (you cry wolf and what do you expect?)), at least try simplifying the integral (ie doing it).
 
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