1. Chapter 8 Class 11 Sequences and Series
  2. Serial order wise
  3. Ex 8.2
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Ex 8.2, 1 - Chapter 8 Class 11 Sequences and Series

Last updated at Dec. 16, 2024 by Teachoo

Transcript

Ex 8.2, 1 Find the 20th and nth terms of the G.P. 5/2, 5/4, 5/8,…. G.P. is 5/2, 5/4, 5/8,…. 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, First term a = 5/2 Common ratio r = (5/4)/(5/2) = 5/4 × 2/5 = 1/2 We need to find nth term, nth term of GP = an = arn-1 Putting a = 5/2 , d = 1/2 = 5/2 (1/2)^(𝑛−1) = 5/2 (1/2^(𝑛−1) ) = (5/(〖2 (2〗^(𝑛−1)))) = 5/(2)"n − 1 + 1" = 5/2^𝑛 Hence, the nth term of GP is 5/2^𝑛 For 20th term of GP Putting n = 20 in an a20 = 5/2^20 Thus, 20th term of GP is 5/2^20
  1. Chapter 8 Class 11 Sequences and Series
  2. Serial order wise

    3. Ex 8.2

    Examples →
Examples →
Chapter 8 Class 11 Sequences and Series
Serial order wise

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo