9. Example 1. Find the sum of the first four terms of the
geometric series: 1,2,4,8
1 + 2 + 4 + 8 = ?
15
10. SUM OF A FINITE GEOMETRIC
SEQUENCE
Formula:
𝑺𝒏 =
𝒂𝟏(𝟏 − 𝒓𝒏
)
(𝟏 − 𝒓)
Where:
𝑆𝑛 = the sum of the first n terms
𝑎1 = first term
𝑟 = common ratio
𝑛 = number of terms
11. Find the sum of the first five terms of the
geometric series:
1, 2,4,8…
12. What is the sum of the first 7 terms
of a finite geometric series if the
first term a1 = 1 and the common
ratio (r) = 2?