# Misc 7 - Chapter 9 Class 11 Sequences and Series

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Misc 7 If f is a function satisfying f (x + y) = f(x) f(y) for all x, y N such that f(1) = 3 and , find the value of n. Given that : f (x + y) = f(x) f(y) x, y N and f(1) = 3 f (1) = 3 f (2) = 9 = 3 2 f (3) = 27 = 3 3 f (4) = 81 = 3 4 Similarly, f (5) = 3 5 f (6) = 3 6 Thus our series is 3, 3 2 , 3 3 , 3 4 , n terms This is a GP, where a = 3 r = 3 2 3 =3 Given sum of GP = 120 = ( 1) 1 Putting a = 3, r = 3 & sum = 120 120 = 3( 3 1) 3 1 3( 3 1) 2 = 120 3 1 = 120 2 3 3 1 = 40 2 3 = 80 3 = 80 + 1 3 = 80 3 = 3 4 n = 4 n = 4

Miscellaneous

Misc 1

Misc 2

Misc 3 Important

Misc 4

Misc 5

Misc 6

Misc 7 Important You are here

Misc 8

Misc 9

Misc 10

Misc 11

Misc 12

Misc 13

Misc 14

Misc 15

Misc 16 Important

Misc 17

Misc 18

Misc 19 Important

Misc 20

Misc 21

Misc 22

Misc 23

Misc 24

Misc 25 Important

Misc 26

Misc 27

Misc 28 Important

Misc 29

Misc 30

Misc 31

Misc 32 Important

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.