Last updated at Dec. 13, 2024 by Teachoo
Ex 5.3, 3 In an AP (i) Given a = 5, d = 3, an = 50, find n and Sn. Given a = 5 , d = 3 , an = 50 We know that an = a + (n – 1) d Putting values 50 = 5 + (n – 1) ×3 50 = 5 + 3n – 3 50 = 2 + 3n 50 – 2 = 3n 48 = 3n 48/3=𝑛 n = 16 Now we need to find Sn Sn = 𝒏/𝟐(𝟐𝒂+(𝒏−𝟏)𝒅) Putting n = 16, a = 5, d = 3 = 16/2 (2 × 5+(16−1) × 3) = 8 (10+15 × 3) = 8(10+45) = 8 ×55 = 440 So, answer is n = 7 and a = –8
Ex 5.3
Ex 5.3, 1 (ii)
Ex 5.3, 1 (iii) Important
Ex 5.3, 1 (iv)
Ex 5.3, 2 (i)
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Ex 5.3, 3 (i) You are here
Ex 5.3, 3 (ii)
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About the Author
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