

Permutations & Combinations  In several fields of mathematics the term permutation is used with different but closely related meanings. They all relate to the notion of mapping the elements of a set to other elements of the same set, i.e., exchanging (or "permuting") elements of a set.
In combinatorial mathematics, a combination is an unordered collection of distinct elements, usually of a prescribed size and taken from a given set. (An ordered collection of distinct elements would sometimes be called a permutation, but that term is ambiguous.) Given such a set S, a combination of elements of S is just a subset of S, where, as always for (sub)sets the order of the elements is not taken into account (two lists with the same elements in different orders are considered to be the same combination). Also, as always for (sub)sets, no elements can be repeated more than once in a combination; this is often referred to as a "collection without repetition". For instance, {1,1,2} is not a combination of three digits; as a set this is the same as {1,2,1} or as {2,1,1}. On the contrary, a poker hand can be described as a combination of 5 cards from a 52card deck: the order of the cards doesn't matter, and there can be no identical cards among the 5.  Wikipedia

  Where: n = total number of items in the group R = number of items chosen from the group 
 






Copyright: 1996  2024 Webmaster:
Kirt Blattenberger, BSEE  KB3UON 
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas
and reference material while performing my work as an RF system and circuit design engineer.
The Internet was still largely an unknown entity at the time and not much was available
in the form of WYSIWYG
...
All trademarks, copyrights, patents, and other rights of ownership to images and text
used on the RF Cafe website are hereby acknowledged.
My Hobby Website: AirplanesAndRockets.com

