9.1 sequence and summation notation

Sequence:

 Domain infinite sequence: positive intergers

              Finite sequence: the first n positive intergers only

 Ex : find the two terms of a sequence of an= 3n-2

        A1= 3(1)-2= 1

        A2= 3(2)-2= 4

 Ex: write an expression for the apparent pattern 

       N= 1 2 3 4 ...n

       Terms: 1 3 5 7 ... An

       Pattern: 2n-1

Factorial:

 N!= 1*2 *3 *4...*(n-1)*n 

 0!=1 

Summation notation

                                n

Ai= a1+a2+a3+a4+...+an

                     i=1

I= index of summation

N= upper limit

1= lower limit