Use the formula for S n to find the sum of the first five terms of the geometric sequence.
-$a _ { 1 } = 8.622 , r = 3.579$ (Round to the nearest hundredth)
A) $- 1412.26$
B) $227.31$
C) $1959.86$
D) $545.19$

Question

Quizplus · Accepted Answer

The sum of the first n terms of a geometric sequence is given by $ S_n = a_1 \frac{r^n - 1}{r - 1} $. Substituting $ a_1 = 8.622 $, $ r = 3.579 $, and $ n = 5 $, we calculate $ S_5 = 8.622 \frac{3.579^5 - 1}{3.579 - 1} \approx 1959.86 $.

Use the Formula for Sn to Find the Sum of the First

Use the Formula for S_n to Find the Sum of the First