# RD Sharma Solutions Class 11 Some Special Series

## RD Sharma Solutions Class 11 Chapter 21

In this chapter, we will discuss the sum of n terms of some special series such as series of natural numbers, series of square of natural numbers, series of cube of natural numbers etc, which mathematically is given as-

Sum of first n natural number: $1+2+3+….+n = \frac{n (n+1)}{2}$

Sum of square of first n natural numbers: $1^{2}+2^{2}+3^{2}+………n^{2} = \frac{n(n+1)(2n+1)}{6}$

Sum of cube of first n natural numbers: $1^{3}+2^{3}+3^{3}+………n^{3} = \left ( \frac{n(n+1)}{2} \right )^{2}$

Sum of fourth power of first n natural numbers: $1^{4}+2^{4}+3^{4}+………n^{4} = \frac{n(n+1)(2n+1)(3n^{2}+3n-1)}{30}$<

All these special series can be used for addition, subtraction of terms to form another special series.

RD Sharma textbook for class 11 Maths is based on latest syllabus prescribed by CBSE. Practice solved solution for the topics ‘Some Special Series’ in order to have a better knowledge about the topics.

Our RD Sharma class 11 solution will help you to understand the concepts and how to approach complicated math problems.

 Chapter 21  Some Special Series Some Special Series Exercise 21.1 Some Special Series Exercise 21.2

#### Practise This Question

From the graph tell how many of the fruits have more sales on Monday than Tuesday.