MAT 1348 Final:

• School: University of Ottawa
• Department: Mathematics
• Course: MAT 1348
• Professor: Guy Beaulieu

Document Summary

When counting objects we need to distinguish between situations where the order matters or not. However, if we are choosing two people from the same group of ve, say both for the same role of vice-presidents, then the order does not matter. For counting problems where the elements need to be arranged in a particular ordering (ordered arrangement) we will refer to permu- tations. When the counting problem requires us to consider elements not arranged in a particular order (unordered arrangement) we will refer to combinations. The notion of factorials will come in handy when computing per- mutations and combinations. Defn: for any positive integer n, n! (read: n factorial) is de ned as n! Defn: an r-permutation from an n-set s is an ordered arrange- ment of r elements of s. P(n, r) denotes the number of r-permutations from an n-set. Defn: an r-combination from an n-set s is an unordered selec- tion of r elements of s.