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Last updated at May 29, 2018 by Teachoo

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Example 3 Let the sequence an be defined as follows: a1 = 1, an = an – 1 + 2 for n ≥ 2. Find first five terms and write corresponding series. It is given- that a1 = 1, For a2 and onward we use this formula. an = an – 1 + 2 for n ≥ 2 Putting n = 2 in (1) a2 = a2 – 1 + 2 a2 = a1 + 2 = 1 + 2 = 3 Putting n = 3 in (1) a3 = a3 – 1 + 2 a3 = a2 + 2 = 3 + 2 = 5 Putting n = 4 in (1) a4 = a4 – 1 + 2 a4 = a3 + 2 = 5 + 2 = 7 Putting n = 5 in (1) a5 = a5 – 1 + 2 a5 = a4 + 2 = 7 + 2 = 9 Hence, the first five terms are 1, 3, 5, 7 and 9. The corresponding series is 1 + 3 + 5 + 7 + 9 +...

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.