Question

Find the sum of the geometric series given a₁ = 2, r = -3, and n = 8.A. 1/2B.-3107OC.-3280D. -3780Reset Selection

Answer 1

The formula to calculate the sum of a geometric sequence is given to be:

$S_n=\frac{a_1(1-r^n)}{1-r}$

The question has the following parameters:

$\begin{gathered} a_1=2 \\ r=-3 \\ n=8 \end{gathered}$

Therefore, the sum will be:

$\begin{gathered} S_8=\frac{2(1-(-3)^8)}{1-(-3)} \\ S_8=-3280 \end{gathered}$

The correct option is OPTION C.