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Common ratio of geometric series

Use the geometric sequence of numbers 1, 3, 9, 27, ... to find the following:

a) What is r, the ratio between 2 consecutive terms?
b) Using the formula for the nth term of a geometric sequence, what is the 10th term?
c) Using the formula for the sum of a geometric series, what is the sum of the first 10 terms?

Solution Preview

The ratio between two consecutive terms is 3/1 = 9/3 = 27/9 ... = 3
10th term is a*r^9 = 1*3^9 = 19683

The sum of 10 ...

Solution Summary

The solution uses simply, step by step calculations to determine the ratio between the terms, the 10th term, and the sum of the first 10 terms.