MATH 3103 Lecture Notes - Lecture 2: Royal Institute Of Technology
24 Aug 2016
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Document Summary
Build each outcome using a series of steps. Step 1 can be done in n1 ways. Step 2 can be done in n2 ways. Step r can be done in nr ways. Then the entire sequence can be done in n1*n2***nr ways. The number of possible outcomes is also n1*n2***nr provided each different choice at any step produces a different outcome. Choose wether or not to add the first: 2 way. Permutations: a permutation of n things taken k at a time: is a selection of k of the n things arranged in order. Example: {1,2,3}, permutation of 3 things taken 2 at a time: {1,3},{2,3},{1,2},{3,1},{3,2},{2,1} n-set=set with n elements. P(n,k)= number of permutation of n things, k at a time. 1:_ 2:_ 3:_ 4:_ 5:_ 6:_. k positions. Step 1: choose an element for the 1st position: n ways. Step 2: choose an element for the 2nd position: n-1 ways.
