# Series and Sequences

Series and sequences : Arrangement of numbers in a definite order is called sequences and addition of such sequences is called series.
Sequences : A succession of numbers of which one number is designated as first, another as second, third and so on that gives us sequence.
In our daily life sequences are used in bank for fixed deposit, radioactive materials disintegrate in a sequence.
Sequences are such series in which there is always a relation between consecutive numbers. On the basis of this relation, there are three types of sequences : Arithmetic , Geometric and Harmonic sequences.
Sequences means the arrangement of numbers in a definite order according to some rule. We denote the terms of sequences as $a_{1},a_{2},a_{3},...a_{n}$ and $a_{1} + a_{2}+ a_{3}+...+ a_{n}$ are series. Subscripts denote the position of the term. nth term is the general term of the sequence.

## Examples on Series and Sequences

1) 2,4,6,8,10,12
Here, $a_{1}$ = 2
$a_{2}$ = 4
$a_{3}$ = 6
$a_{4}$ = 8
$a_{5}$ = 10
$a_{6}$ = 12
Here there are 6 terms