No products in the cart.

What is the formula for sum …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

What is the formula for sum of n terms of G.P
  • 2 answers

Śěřãj The Cute? 4 years, 3 months ago

Sn=a[r^n-1]/r-1

Gaurav Seth 4 years, 3 months ago

Let ‘a’ be the first term and ’r’(≠) be the common ratio of the given G.P.The general teams of G.P. If Sn denotes the sum of ‘n’ terms, then,

Sn = a((1 - rn)/(1 - r)) r ≠ 1

This can also written as

Sn = a((rn - 1)/(r - 1))

Note: (1) Sn = a + ar + ar+….. +arn-1 

(2) If r = 1, then Sn = a + a + a +……………+a – na 

(3) If r = 1, then formulas for Sn fail 

(4) If r < 1, then use  Sn = a((1 - rn)/(1 - r))

(5) If r > 1, use  Sn = a((rn - 1)/(r - 1))

(6) Sum of an infinite G.P.,a + ar + ar2  + ..... is a/(1 - r), - 1 r < 1

(7) If a, b, c are in G.P.then ‘b’ is the G.M. (geometric mean) between a and c, then b2  = ac ⇒ b = √ac

(8) If A and G are A.M. and G.M. of two given distinct positive real numbers, then relation between A and G is A > G.

http://mycbseguide.com/examin8/

Related Questions

Express the complex number i-39
  • 0 answers
(3+i)x + (1-2i) y +7i =0
  • 1 answers
Find the product. (4x²) (–5³)
  • 0 answers
Square of 169
  • 1 answers
2nC2:nC3=33:10
  • 0 answers
Ch 1 ke questions
  • 1 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App