NCERT Solutions for Class 11 Maths Exercise 9.2 Sequences and Series in English and Hindi Medium updated for new academic session 2022-2023. All the questions of Exercise 9.2 are solved in simple explanation through PDF and Video.

## NCERT Solutions for Class 11 Maths Exercise 9.2

### Series and its Sum

A series is the sum if the various terms of a sequence. As per the NCERT Solution Class 11 Maths, the sequence is a₁, a ₂, a₃ . . . aₙ the expression a₁, + a ₂ + a₃ + . . . + aₙ is known as the series. Generally, a series is shown by S and Greek symbol sigma indicates the summation of the series.

The series is finite or infinite which is directly linked with the given sequence if it is finite or infinite. One of the important facts that you must note is that when the series is used the phrase using SUM OF A SERIES means you must add the terms. For example, 1 + 3 + 5 + 7 is a finite series with four terms which gives you some of the series is 16.

#### Arithmetic progression – AP

At the beginning of exercise 9.2, we have studied what is sequence and series. The series described as a₁, a ₂, a₃ . . . aₙ. . . is known as an arithmetic sequence. There are total 18 questions in class 11 Maths exercise 9.2 for practice. All the questions are tricky and important for the exams.

We can define an arithmetic sequence as a list of numbers with a pattern that is definite. If you choose any number and subtract it by each term of the AP. The outcome you will receive will always be an arithmetic sequence.

##### Questions of Class 11 Maths Exercise 9.2

The questions given in Exercise 9.2 of 11th Maths easy but time consuming. Student needs regular practice to be confident in this exercise. The basic knowledge of AP is required here. In definition, you can see the formula of arithmetic progression and along with it the first term and common difference.

The common difference is the constant gap in all pairs of consecutive or successive numbers in a sequence. The use of this common difference is to take the current term and add the common difference then you will obtain the next term. This is the process used to generate the terms in the sequence.

###### Features of AP for the practice of Exercise 9.2 in 11th Maths

(a) If a constant is added to every term of an arithmetic progression, then its outcome will also be an arithmetic progression. (b) If you subtract a constant from each term of an A.P. then the outcome of the sequence is also an A.P.

(c) If you multiply each term of an A.P. with a constant, then the resulting sequence is also an A.P. and (d) if you divide each term of A.P. by non–zero constant then the resulting sequence is also an A.P. These are some of the important properties that you must learn and keep in mind all the time.       