Subscribe to our Youtube Channel - https://you.tube/teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex9.3, 11 Introduction (2 + 3k) At k = 1, 2 + 31 At k = 2, 2 + 32 .. โฆ โฆ. At k = 11, 2 + 311 Ex9.3, 11 We calculate (31 + 32 + 33 + โฆ + 311) separately In 31 + 32 + 33 + โฆ + 311 32/31 = 3 & 33/32 = 3 Thus, (๐๐๐๐๐๐ ๐ก๐๐๐)/(๐น๐๐๐ ๐ก ๐ก๐๐๐) = (๐โ๐๐๐ ๐ก๐๐๐)/(๐๐๐๐๐๐ ๐ก๐๐๐) i.e. common ratio is same Thus, it is a G.P. First term = a = 3 Common ratio = 3^2/3^1 = 3 Since, r > 1 โด Sn = (๐(๐^๐ โ 1))/(๐ โ 1) where Sn = sum of n terms of GP n is the number of terms a is the first term & r is the common ratio โด Sn = (๐(๐^๐ โ 1))/(๐ โ 1) Putting values a = 3 , r = 3, n = 11 S11 = (3[311โ1])/(3 โ 1) S11 =(3[311โ1])/2 Hence 31 + 32 + โฆ + 311 = (3[311โ1])/2 From (1) Putting 31 + 32 + โฆ + 311 = (3[311โ1])/2 = 22 + (3(311 โ 1))/2 =22 + 3/2(311 โ1) Therefore,

Ex 9.3

Ex 9.3, 1

Ex 9.3, 2

Ex 9.3, 3 Important

Ex 9.3, 4

Ex 9.3, 5

Ex 9.3, 6

Ex 9.3, 7

Ex 9.3, 8

Ex 9.3, 9

Ex 9.3, 10

Ex 9.3, 11 Important You are here

Ex 9.3, 12

Ex 9.3, 13

Ex 9.3, 14

Ex 9.3, 15

Ex 9.3, 16

Ex 9.3, 17 Important

Ex 9.3, 18 Important

Ex 9.3, 19

Ex 9.3, 20

Ex 9.3, 21

Ex 9.3, 22 Important

Ex 9.3, 23

Ex 9.3, 24

Ex 9.3, 25

Ex 9.3, 26

Ex 9.3, 27 Important

Ex 9.3, 28 Important

Ex 9.3, 29 Important

Ex 9.3, 30

Ex 9.3, 31

Ex 9.3, 32

Chapter 9 Class 11 Sequences and Series

Serial order wise

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.