Example 11 - Find sum of first 22 terms of AP: 8, 3, -2, ..

Example 11 - Chapter 5 Class 10 Arithmetic Progressions - Part 2

  1. Chapter 5 Class 10 Arithmetic Progressions
  2. Serial order wise

Transcript

Example 11 Find the sum of the first 22 terms of the AP : 8, 3, –2, . . . Given 8, 3, –2,………… We have to find sum of first 22 terms . Here, n = 22, a = 8 d = 3 – 8 = –5 Putting there values in formula, Sum = 𝑛/2 [2𝑎+(𝑛−1)𝑑] = 22/2[2 × 8+(22−1)(−5)] = 11[16+(21)(−5)] = 11[16−105] = 11[− 89] = –979

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.