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Ex 5.2, 9 - Chapter 5 Class 10 Arithmetic Progressions
Last updated at May 29, 2023 by Teachoo
Ex 5.2
Ex 5.2, 1
Ex 5.2, 2 (i) (MCQ)
Ex 5.2, 2 (ii) (MCQ) Important
Ex 5.2, 3 (i)
Ex 5.2, 3 (ii)
Ex 5.2, 3 (iii) Important
Ex 5.2, 3 (iv)
Ex 5.2, 3 (v) Important
Ex 5.2, 4
Ex 5.2, 5 (i)
Ex 5.2, 5 (ii) Important
Ex 5.2, 6 Important
Ex 5.2, 7
Ex 5.2, 8
Ex 5.2, 9 You are here
Ex 5.2, 10
Ex 5.2, 11
Ex 5.2, 12 Important
Ex 5.2, 13 Important
Ex 5.2, 14 Important
Ex 5.2, 15
Ex 5.2, 16
Ex 5.2, 17 Important
Ex 5.2, 18
Ex 5.2, 19
Ex 5.2, 20 Important
Chapter 5 Class 10 Arithmetic Progressions
Serial order wise
Transcript
Ex 5.2, 9 If the 3rd and the 9th terms of an A.P. are 4 and − 8 respectively. Which term of this A.P. is zero. We know that an = a + (n – 1) d Given 3rd term is 4 a3 = a + (3 – 1) d 4 = a + 2d 4 – 2d = a a = 4 – 2d Given 9th term is –8 a9 = a + (9 – 1) d –8 = a + 8d –8 – 8d = a a = –8d – 8 From (1) & (2) 4 – 2d = –8d – 8 –2d + 8d = –8 – 4 6d = –12 d = (−12)/6 d = –2 Putting value of d in (2) a = 4 – 2d = 4 – 2 × (–2) = 4 + 4 = 8 We need to check which term is 0 Lets assume it is nth term of AP So, an = 0, Also, a = 8 & d = – 2 We know that an = a + (n – 1)d Putting values 0 = 8 + (n – 1) × – 2 0 = 8 + n × ( – 2) – 1 × (– 2) 0 = 8 – 2n + 2 0 = 10 – 2n 2n = 10 n = 10/2 n = 5 ∴ 5th term of AP is 0
