Do These Infinite Series Converge?

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SUMMARY

The discussion focuses on the convergence of two infinite series: $\displaystyle \sum_{n=0}^{\infty} \frac{n!}{n! + 3^n}$ and $\displaystyle \sum_{n=1}^{\infty} (n - \frac{1}{n})^{-n}$. The first series can be analyzed using the limit comparison test, specifically evaluating $\displaystyle \lim_{n \rightarrow \infty} \frac{n!}{n! + 3^n}$, which approaches 1, indicating convergence. The second series is noted to be undefined at n=1, suggesting that further investigation into its behavior is necessary.

PREREQUISITES
  • Understanding of infinite series and convergence tests
  • Familiarity with factorial notation and its properties
  • Knowledge of limit comparison tests in calculus
  • Basic concepts of undefined expressions in mathematical series
NEXT STEPS
  • Study the Limit Comparison Test in detail
  • Explore the behavior of factorials in series convergence
  • Investigate the implications of undefined expressions in series
  • Learn about other convergence tests such as the Ratio Test and Root Test
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Mathematics students, educators, and anyone studying series convergence in calculus or advanced mathematics.

Tebow15
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Test these for convergence.

1.
infinity
E...n!/(n! + 3^n)
n = 0

2.
infinity
E...(n - (1/n))^-n
n = 1

Btw, E means sum.

Which tests should I use to solve these?
 
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cacophony said:
1. $\displaystyle \sum_{n=0}^{\infty} \frac{n!}{n! + 3^n}$

What is $\displaystyle \lim_{n \rightarrow \infty} \frac{n!}{n! + 3^n}$?...

Kind regards

$\chi$ $\sigma$
 
cacophony said:
2.
infinity
E...(n - (1/n))^-n
n = 1

This sum is undefined at n=1 !
 

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