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Last updated at May 29, 2018 by Teachoo

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Example 1 Write the first three terms in each of the following sequences defined by the following: an = 2n + 5 We need to find first three terms i.e. a1, a2, a3 Given an = 2n + 5 putting n = 1 in (1) a1 = 2(1) + 5 = 2 + 5 = 7 Putting n = 2 in (1) a2 = 2(2) + 5 = 4 + 5 Putting n = 3 in (1) a3 = 2(3) + 5 = 6 + 5 = 11 Hence first three terms are 7, 9 and 11. Example 1 Write the first three terms in each of the following sequences defined by the following: (ii) an = (๐ โ 3)/4 We need to find first three terms a1, a2, a3 an = (๐ โ 3)/4 putting n = 1 in (1) a1 = (1 โ 3)/4 = (โ2)/4 = (โ1)/2 Putting n = 2 in (1) a2 = (2 โ 3)/4 a2 = ( โ1)/4 Putting n = 3 in (1) a3 = (3 โ 3)/4 a3 = 0/4 a3 = 0 Hence first three terms are โ1/2, โ1/4, 0

Chapter 9 Class 11 Sequences and Series

Concept wise

- Finding Sequences
- Arithmetic Progression (AP): Formulae based
- Arithmetic Progression (AP): Statement
- Arithmetic Progression (AP): Calculation based/Proofs
- Inserting AP between two numbers
- Arithmetic Mean (AM)
- Geometric Progression(GP): Formulae based
- Geometric Progression(GP): Statement
- Geometric Progression(GP): Calculation based/Proofs
- Inserting GP between two numbers
- Geometric Mean (GM)
- AM and GM (Arithmetic Mean And Geometric mean)
- AP and GP mix questions
- Finding sum from series
- Finding sum from nth number

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.