ClassNotes-Math-Factorials

ClassNotes-Math-Factorials - Sven Thommesen 2011 Math:...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 © Sven Thommesen 2011 Math: Factorials, combinations, permutations (Needed in Ch 4) [Edited 09/23/08] [This note merely defines some mathematical concepts we’ll need. The chapter notes will tell you when and how to use these concepts.] In order to discuss how to calculate probability in various contexts, we need to define the following new mathematical concepts: (a) FACTORIALS The factorial is used to calculate the answer to the following question: How many different sequences, or permutations , can we form from a group of N items? Definition: the factorial N! = 1 2 3. .. 1 N iN i    and we define 0! = 1 For example: 2! = 2 x 1 = 2 5! = 5 x 4 x 3 x 2 x 1 = 120 For example, how many different ways can we line up 4 cars in a row? The answer is: 4! = 4 x 3 x 2 x 1 = 24 ways. To see how: for the first spot in the lineup we can pick either of the 4 different cars. For the second spot, we have only 3 left to choose from. For the third spot, there are 2 left. And for the last spot, there’s only one car left, since the other 3 have been taken. So the number of possible ways we
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This document was uploaded on 09/23/2011.

Page1 / 3

ClassNotes-Math-Factorials - Sven Thommesen 2011 Math:...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online