Lim n to infinity for factorial

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SUMMARY

The limit as n approaches infinity for (n!)^(1/n) is evaluated using Stirling's formula, which approximates n! as √(2πn)(n/e)^n. This leads to the conclusion that lim n -> ∞ (n!)^(1/n) approaches infinity, as the dominant term (n/e) contributes significantly to the growth of the factorial. The discussion emphasizes the importance of understanding the behavior of individual terms in the product and their limits as n increases.

PREREQUISITES
  • Understanding of limits in calculus
  • Familiarity with factorial functions
  • Knowledge of Stirling's approximation
  • Basic concepts of sequences and series
NEXT STEPS
  • Study Stirling's approximation in detail
  • Explore the properties of limits involving products
  • Learn about asymptotic analysis in mathematical sequences
  • Investigate the behavior of exponential functions as n approaches infinity
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Mathematics students, educators, and anyone interested in advanced calculus and asymptotic analysis will benefit from this discussion.

noobiez
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Homework Statement


lim n -> infinity for (n!)^(1/n)


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The Attempt at a Solution


hmm, i know that lim n approaches infinity, (n)^(1/n) will go to 1, but issit the same for n!?
 
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You might do this: n!= 1*2*3*...* (n-1)*n so it has exactly n factors. (n!)^(1/n)= (1)^(1/n)(2)^(1/n)(3)^(1/2)*...*(n-1)^(1/n)*n^(1/n). Now you say that you know that n^(1/n) goes to 1. What do you think the other numbers go to? In particular, what does 2^(1/n) or 3^(1/n) go to? If you don't know try looking at 2^(1/100000) or 3^(1/100000). What does the product of thing like that go to?
 
HallsofIvy said:
You might do this: n!= 1*2*3*...* (n-1)*n so it has exactly n factors. (n!)^(1/n)= (1)^(1/n)(2)^(1/n)(3)^(1/2)*...*(n-1)^(1/n)*n^(1/n). Now you say that you know that n^(1/n) goes to 1. What do you think the other numbers go to? In particular, what does 2^(1/n) or 3^(1/n) go to? If you don't know try looking at 2^(1/100000) or 3^(1/100000). What does the product of thing like that go to?

?? All of those limits may be one. But the limit of the product certainly isn't one. Use Stirling's formula for n!.
 

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