NCERT Solutions for Class 11 Maths, Chapter 9 - Sequences and Series

In this chapter, you’ll study Sequences and Series. A sequence is a collection of objects or events listed in a particular order. All the items or objects in a sequence are called terms. For instance, (2, 4, 6, 8……20) is a sequence and these numbers are called its terms. Sequences can be arithmetic sequences or geometric sequences. On the other hand, a series is the sum of the list items. For instance, a series can be S = Sum (2, 4, 6, 8……20). The series can be finite or infinite according to the given sequence, whether it is finite or infinite. In NCERT Solutions for Class 11, Chapter 9, you’ll also learn about  arithmetic mean, geometric mean, relationship between A.M. and G.M., special series in forms of sum to ‘n’ terms of consecutive natural numbers, sum to ‘n’ terms of squares of natural numbers and sum to ‘n’ terms of cubes of natural numbers and more.

Sequences and Series have many real-life applications and are used in every sphere of life, such as the flat numbers assigned in an apartment, the amount in your savings account, height of students in a class, increasing population of a city, and much more.

Let’s take a look at topics and sub-topics of Class 11 Maths Chapter 9,  Sequences and Series

9.1 Introduction

9.2 Sequences

9.3 Series

9.4 Arithmetic Progression (A.P.)

9.5 Geometric Progression (G.P.)

9.6 Relationship Between A.M. and G.M.

9.7 Sum to n terms of Special Series

In Class 11 Maths Chapter 9, you will learn – 

Section 9.2 – In this section, you’ll learn what sequences are. You’ll also study how sequences are denoted, the difference between finite and infinite sequences and when a sequence is regarded as a function.

Section 9.3 – In this section, you’ll learn what series are. You’ll also learn about finite and infinite series and how to represent series in compact form using the Greek letter ∑ (sigma).

Section 9.4 – In this section, you’ll acquire knowledge when a sequence is called an arithmetic progression is (A.P.). You’ll also learn what an arithmetic mean is and how to verify some simple properties and notations of an arithmetic progression.

Section 9.5 – In this section, you’ll learn when a sequence is called Geometric Progression (G.P.) and the difference between finite and infinite Geometric progression. You’ll also study how to find the common ratio and geometric mean.

Section 9.6 – In this section, you’ll learn about the relation between Arithmetic Progression and Geometric Progression. You’ll solve problems where A.M. and G.M. are given and you need to find the numbers.

Section 9.7 – In this section, you’ll learn how to find the sum of first ‘n’ terms of some special series, namely the sum of first n natural numbers, the sum of squares of the first ‘n’ natural numbers and the sum of cubes of the first ‘n’ natural numbers.

In this chapter, you are provided with several examples along with their solutions for a clear understanding of Sequences and Series. To know more about Class 11 Maths Chapter 9 Sequences and Series, you should explore the exercises below. You can also download the Sequences and Series Class 11 NCERT Solutions PDF, solved by expert Maths trainers.