Simplifying Combination Formula: \binom{n}{\frac{n}{2}} using Factorial Formula

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SUMMARY

The discussion focuses on simplifying the combination formula \binom{n}{\frac{n}{2}} using the factorial formula \frac{n!}{(\frac{n}{2})!(\frac{n}{2})!}. The user derived an expression involving 2^{n} and a series of terms (1-\frac{1}{n})(1-\frac{1}{n-2})(1-\frac{1}{n-4})... but sought further simplification. Participants recommended utilizing Stirling's approximation to analyze the behavior of the formula as n increases, emphasizing its importance in probability theory.

PREREQUISITES
  • Understanding of combination formulas and factorials
  • Familiarity with Stirling's approximation
  • Basic knowledge of probability theory
  • Ability to manipulate algebraic expressions
NEXT STEPS
  • Research Stirling's approximation and its applications in combinatorics
  • Explore the asymptotic behavior of \binom{n}{\frac{n}{2}} as n approaches infinity
  • Learn about the implications of large n in probability distributions
  • Study advanced combinatorial identities and their proofs
USEFUL FOR

Students of mathematics, particularly those studying combinatorics and probability, as well as educators looking to deepen their understanding of factorials and approximation techniques.

Aleoa
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I'm trying to simplify the combination defined as : \binom{n}{\frac{n}{2}}.

I did some calculations, starting from the factorial formula \frac{n!}{(\frac{n}{2})!(\frac{n}{2})!} and i found this form :

2^{n}(1-\frac{1}{n})(1-\frac{1}{n-2})(1-\frac{1}{n-4})...

but i don't know how to continue, can you help me ?
 
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Aleoa said:
but i don't know how to continue, can you help me ?
No, since you haven't said what your goal is. To me ##\binom{n}{\frac{n}{2}}## is already fine.
 
I want to characterize the behaviour of the formula as n become larger, so I'm trying to simplify it . I'm sorry for the template, next time i'll write it correctly. Thanks for the support
 
Aleoa said:
I want to characterize the behaviour of the formula as n become larger, so I'm trying to simplify it . I'm sorry for the template, next time i'll write it correctly. Thanks for the support
In this case I'd try where Stirling's approximation would get me.
 
Aleoa said:
I want to characterize the behaviour of the formula as n become larger, so I'm trying to simplify it . I'm sorry for the template, next time i'll write it correctly. Thanks for the support

As fresh_42 suggested, use Stirling's formula. Every student of probability should be thoroughly familiar with that formula, as it is used everywhere.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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