Factorials; Permutations; Homework for 2014-09-08


We learned about Factorial Notation and about Permutations today:

Factorial: n!=n\times(n-1)\times\ldots\times2\times1

Number of permutations of n distinct objects: _nP_n = P(n,n) = n!

Number of arrangements of r distinct objects from a group of n distinct objects: _nP_r = P(n,r) = \frac{n!}{(n-r)!}

Homework was page 239. We completed #1 and #2 in class, and you’re finishing #6, 7 and 9 tonight. 

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