246,743 views
18 votes
18 votes
What is the correct formula to find the sum of the finite geometric series below?


image

User Marcelo Boeira
by
2.7k points

2 Answers

24 votes
24 votes

Explanation:


image

r =
image

r =
image

r =
image

Soo :


image


image


image

User Hoyen
by
2.5k points
24 votes
24 votes

We are given the Geometric Series:


image

which can be rewritten as:


image

here, we can see that every term is (1/3) times the last term

Hence, we can say that the common ratio of this Geometric Series is 1/3

Finding the Sum:

We know that the sum of a Geometric Series is:


image

(where r is the common ratio, a is the first term, and n is the number of terms)

another look at the given Geometric Series tells us that the first term is 2 and the number of terms is 7

plugging these values in the formula, we get:


image


image

Sₙ = 2.97

User Raygerrard
by
2.3k points