Difference between revisions of "Binomial coefficient"

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[[Binomial theorem]]
<strong>Theorem (Binomial Theorem):</strong> $(a+b)^n = \displaystyle\sum_{k=0}^n {n \choose k} a^k b^{n-k}$
 
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<strong>Proof:</strong> █
 
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=Videos=
 
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Revision as of 02:18, 4 June 2016

The binomial coefficients are defined by the formula $${}_nC_k:={n \choose k} = \dfrac{n!}{(n-k)!k!}.$$


Properties

Proposition: $\displaystyle{n \choose k} = {n \choose {n-k}} = (-1)^k {{k-n-1} \choose k}$

Proof:

Proposition: $\displaystyle{{n+1} \choose k} = {n \choose k} + {n \choose {k-1}}$

Proof:

Proposition: ${n \choose 0} = {n \choose n} = 1$

Proof:

Proposition: $1 + \displaystyle {n \choose 1} + {n \choose 2} + \ldots + {n \choose n} = 2^n$

Proof:

Proposition: $1 - \displaystyle {n \choose 1} + {n \choose 2} - \ldots + (-1)^n {n \choose n} =0$

Proof:

Binomial theorem

Videos

Pascal's Triangle and the Binomial Coefficients
Example of choose function (Binomial Coefficient)
Binomial coefficients

References

Abramowitz and Stegun
The Binomial Coefficient Function