1. Chapter 9 Class 11 Sequences and Series
  2. Serial order wise
  3. Ex 9.3

Ex 9.3, 2 - Class 11

Last updated at May 29, 2018 by

Ex 9.3, 2 - Find 12th term of GP whose 8th term is 192 - Geometric Progression(GP): Formulae based

  1. Chapter 9 Class 11 Sequences and Series
  2. Serial order wise
    3. Ex 9.3
    Ex 9.4 →
Ask Download

Transcript

Ex9.3,2 Find the 12th term of a G.P. whose 8th term is 192 and the common ratio is 2. We know that an = arn – 1 where an = nth term of GP n is the number of terms a is the first term r is the common ratio Here, common ratio r = 2 & 8th term is 192 i.e. a8 = 192 Putting an = 192, r = 2 and n = 8 in an 192 = a 2^(8−1) 192 = a × 27 192/27 = a a = 192/27 Now we need to find 12th term, we use the formula an = arn – 1 Putting n = 12 , a = 192/27 , r = 2 a12 = 192/27 × (2)12 – 1 = 192/27 × (2)11 = 192(2)11 – 7 = 192(2)4 = 192 × 16 = 3072 Thus, 12th term is 3072

Chapter 9 Class 11 Sequences and Series
Serial order wise

About the Author

Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.