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## NCERT Solutions for Class 11 Maths Chapter 9

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### Class 11 Maths Chapter 9 Sequences and Series Solutions

**Download Exercise 9.1****Download Exercise 9.2****Download Exercise 9.3****Download Exercise 9.4****Download Miscellaneous Exercise 9****Download Supplementary Exercise 9.4****NCERT Books for Class 11****Revision Books for Class 11**- Hindi Medium Solutions will be uploaded very soon.

#### Important Terms Related to Sequences & Series

- A
*sequence*is a function whose domain is the set N of natural numbers or some subset of it. - In an A.P., the sum of the terms equidistant from the beginning and from the end is always same, and equal to the sum of the first and the last term.
- If three terms of A.P. are to be taken then we choose then as a – d, a, a + d.
- If four terms of A.P. are to be taken then we choose then as a – 3d, a – d, a + d, a + 3d.
- If five terms of A.P are to be taken, then we choose then as: a – 2d, a – d, a, a + d, a + 2d.
- A sequence is said to be a progression if the term of the sequence can be expressed by some formula.
- A sequence whose range is a subset of R is called a
*real sequence*. - In a G.P., the product of the terms equidistant from the beginning and from the end is always same and equal to the product of the first and the last term.
- If each term of a G.P. be raised to some power then the resulting terms are also in G.P.
- If a, b, c are in A.P. then 2b = a + c.
- If a, b, c are in G.P. then b² = ac.