CBSE Class 11 Maths Notes: Sequences & Series - Sequence and Progression

SEQUENCE

A succession of numbers formed according to some definite rule is called a sequence. For example 1, 3, 5, 7,9 ……. is a sequence, here each term of the sequence can be obtained by adding 2 to the preceding term.

Types of Sequence

There are two types of sequence.

Finite sequence
Infinite sequence

a sequence is said to be a finite or infinite according as it has finite or infinite number of terms.

Series

If {f_n} be a sequence then an expression of the form f₁ + f₂ + …… + f_n is called series. In other word a series is the sum of the terms of the sequence.

PROGRESSION

If the terms of a sequence are written under specific condition then the sequence is called progression. There are three types of progressions.