3. Permutations and combinations
Robin J. Wilson · Oxford University Press eBooks · 2016
Permutations and combinations have been studied for thousands of years. ‘Permutations and combinations’ considers selecting objects from a collection, either in a particular order (such as when ranking breakfast cereals) or without concern for order (such as when dealing out a bridge hand). It describes and investigates four types of selection—ordered selections with repetition, ordered selections without repetition, unordered selections without repetition, and unordered selections with repetition—and shows how they are related to permutations, combinations, the three combination rules, factorials, Pascal’s triangle, the binomial theorem, binomial coefficients, and distributions.