Ex 5.3, 3 - Chapter 5 Class 10 Arithmetic Progressions - Part 3

Ex 5.3, 3 - Chapter 5 Class 10 Arithmetic Progressions - Part 4

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

Transcript

Ex 5.3, 3 In an AP (ii) Given a = 7, a13 = 35, find d and S13. Given a = 7, a13 = 35 We need to find d We know that an = a + (n โ€“ 1) d Putting a = 7, n = 13 and an = 35 35 = 7 + (13 โ€“ 1) ร— ๐‘‘ 35 = 7 + 12d 35 โ€“ 7 = 12d 28 = 12 d 28/12=๐‘‘ 7/3=๐‘‘ d = ๐Ÿ•/๐Ÿ‘ Now we need to find S13 We can use formula Sn = ๐’/๐Ÿ (๐’‚+๐’) Putting n = 13, a = 7, ๐‘™ = a13 = 35 = 13/2(7+35) = 13/2 ร— 42 = 13 ร— 21 = 273

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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.