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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,631

Combinatorics Formulas

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,009

**Permutations **

The number of Permutations (arrangements) of n different things taken r at a time

where n! = n(n-1)(n-2)(n-3)......4 x 3 x 2 x 1

**Some Important results**

**Combinations**

The number of combinations (selections) of n different things taken r at a time

**Some Important results**

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**All_Is_Number****Member**- Registered: 2006-07-10
- Posts: 258

*Last edited by All_Is_Number (2006-10-01 12:48:10)*

*You can shear a sheep many times but skin him only once.*

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