Question

•How can you represent the terms of a sequence?
•How can you define an arithmetic or geometric sequence?
•How can you model the sum of an arithmetic or geometric series?

Answer 1

take a look at this , everything is there, http://www.purplemath.com/modules/series.htm
short answer for this arithmetic : the next term = previous term +/- a constant. for example : 1,3,5,.... ( 3=1+2, 5 =3+2 ....)
geometric: next term = previous term * (time) a constant, for example 2,4,8,16.....
4 =2*2
8=4*2
16=8*2
got it?