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BodhiAI
Nov. 15, 2019

Introduction,Factorial Notation,Fundamental Principle of Counting(Multiplication & Addition Theorm):

 

Factorial Notation

 

The product of first n natural numbers can be written as (n)!

 

           (n)! = n(n-1) (n-2) .............3.2.1

 

thus; (n)! = n(n-1)! = n(n-1) (n-2)!

 

also; (0)! = 1

 

Fundamental Rule of Association

 

A. Sum Rule

 

Suppose A can occur in m ways and B can occur in n ways and both cannot occur simultaneously. Then A or B (at least one of them) can occur in (m+n) ways. This rule is also applicable for two or more exclusive events.

 

B. Product Rule

 

If there are m ways of doing a thing and when it has been done in any one of these m ways, then there are n ways of doing a second thing, then the total number of ways of doing two things together are m×n.