About Geometric Series Formula
Let us first define what a geometric series is before learning the formula. The ratios of every two consecutive terms are the same in this series (sum of terms). The formula for the geometric series is:
- The nth term of a geometric series can be found using this formula.
- Calculating the sum of finite geometric series
- Calculating the total of an infinite geometric series
What do you mean by Geometric Series?
A geometric series is the sum of a geometric sequence's finite or infinite terms. The corresponding geometric series for the geometric sequences a, ar, ar2,..., arn-1,... is a + ar + ar2 +..., arn-1 +.... "Series" means "sum," as we all know. The geometric series is defined as the sum of phrases with a common ratio between every two adjacent terms. Geometric series come in two varieties: finite and infinite. Here are some geometric series examples.
1/2 + 1/4 +.... + 1/8192 is a finite geometric series in which the first term, a = 1/2, and the common ratio, r = 1/2
-4 + 2 - 1 + 1/2 - 1/4 +... is an infinite geometric series in which the first term, a = -4, and the common ratio, r = -1/2.
Geometric Series Formula
The formula for the sum of a finite geometric sequence, the sum of an infinite geometric sequence, and the nth term of a geometric sequence is known as the geometric series formula. The sequence is a, ar, ar2, ar3,......, with a being the first term and r being the "common ratio."
- an = a · rn - 1
- Sn = a (rn- 1) / (r - 1).
- Sn = a (1 - rn) / (1 - r).
- S∞ = a / (1 - r).
Geometric Series Formulas
The formulas for finding the nth term, the sum of n terms, and the sum of infinite terms are among the formulas for a geometric series. Consider a geometric series with a first term and r as the common ratio.
- a + ar + ar2 + ar3 + ...
Formula : The nth term of a geometric sequence is,nth term = a rn-1 Here, a is the first term
- r is common ratio of every two successive terms
- n is number of terms.
Formula : The sum formula of a finite geometric series a + ar + ar2+ ar3+ ... + a rn-1is
Sum of n terms = a (1 - rn) / (1 - r) (or) a (rn- 1) / (r - 1)
Here,
- a is the first term
- r is the common ratio every two consecutive terms
- n is the number of terms.
Formula : The sum formula of an infinite geometric series a + ar + ar2+ ar3+ ..........is
Sum of infinite geometric series = a / (1 - r)
Here,
- a is the first term
- r is the common ratio every two successive terms
Get the list of all Maths formulas used in general calculations.