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## Sequences and Series Formulas for Class 11 Maths Chapter 9

Are you looking for Sequences and Series formulas for class 11 Chapter 9? Today, we are going to share Sequences and Series formulas for class 11 Chapter 9 according to student requirements. You are not a single student who is searching Sequences and Series formulas for class 11 Chapter 9. According to me, thousands of students are searching Sequences and Series formulas for class 11 Chapter 9 per month. If you have any doubt or issue related to Sequences and Series formulas then you can easily connect with through social media for discussion. Sequence and Serie formulas will very helpful to understand the concept and questions of the chapter Sequences and Series. I would like to suggest you remember Sequences and Series formulas for the whole life. It also helps you with higher studies.

• The nth term an of the Arithmetic Progression (A.P) $$a,{\text{ }}a + d,{\text{ }}a + 2d, \ldots$$ is given by $${a_n} = a + (n – 1)d$$.
• The arithmetic mean between a and b is given by $$A.M = \frac{{a + b}}{2}$$.
• If Sn denotes the sum up to n terms of A.P. $$a,{\text{ }}a + d,{\text{ }}a + 2d, \ldots$$ then $${S_n} = \frac{n}{2}(a + l)$$ where l stands for the last term, $${S_n} = \frac{n}{2}[2a + (n – 1)d]$$
• The sum of n A.M’s between a and b is $$= \frac{{n(a + b)}}{2}$$.
• The nth term an of the geometric progression $$a,{\text{ }}ar,{\text{ }}a{r^2},{\text{ }}a{r^3}, \ldots$$ is $${a_n} = a{r^{n – 1}}$$.
• The geometric mean between a and b is $$G.M = \pm \sqrt {ab}$$.
• If $${S_n}$$ denotes the sum up to n terms of G.P is $${S_n} = \frac{{a(1 – {r^n})}}{{1 – r}};{\text{ }}r \ne 1$$, $${S_n} = \frac{{a – rl}}{{1 – r}};{\text{ }}l = a{r^n}$$ where $$\left| r \right| < 1$$
• The sum S of infinite geometric series is $$S = \frac{a}{{1 – r}};{\text{ }}\left| r \right| < 1$$
• The nth term an of the harmonic progression is $${a_n} = \frac{1}{{a + (n – 1)d}}$$.
• The harmonic mean between a and b is $$H.M = \frac{{2ab}}{{a + b}}$$.

#### Summary Sequences and Series Formulas

We have listed top important formulas for Sequences and Series for class 11 Chapter 9 which helps support to solve questions related to chapter Sequences and Series. I would like to say that after remembering the Sequences and Series formulas you can start the questions and answers the solution of the Sequences and Series chapter. If you faced any problem to find a solution of Sequences and Series questions, please let me know through commenting or mail.

#### NCERT Solutions Class 11 Maths by Chapters

• Chapter 1 Sets
• Chapter 2 Relations and Functions
• Chapter 3 Trigonometric Functions
• Chapter 4 Principle of Mathematical Induction
• Chapter 5 Complex Numbers and Quadratic Equations
• Chapter 6 Linear Inequalities
• Chapter 7 Permutations and Combinations
• Chapter 8 Binomial Theorem
• Chapter 9 Sequences and Series
• Chapter 10 Straight lines
• Chapter 11 Conic Sections
• Chapter 12 Introduction to Three Dimensional Geometry
• Chapter 13 Limits and Derivatives
• Chapter 14 Mathematical Reasoning
• Chapter 15 Statistics
• Chapter 16 Probability