NCERT Class 11 Mathematics Solutions: Chapter 9 –Sequences and Series Miscellaneous Exercise 9 Part 12

Glide to success with Doorsteptutor material for NSTSE : Get full length tests using official NTA interface: all topics with exact weightage, real exam experience, detailed analytics, comparison and rankings, & questions with full solutions.

Formulae for Arithmetic Series

Formulae for Arithmetic Series

Loading image

1. Find the 20th term of the series terms.


The given series is terms


So, the term of the series is .

2. Find the sum of the first n terms of the series:


The given series is

On subtracting both the equations, we obtain