Use a graphing utility to find the sum of the geometric sequence. Round answer to two decimal places, if necessary.
-$4 + 12 + 36 + 108 + 324 + \cdots + 4 \cdot 3 ^ { 10 }$
A) 354,292
B) 354,294
C) 354,329
D) 354,272

Question

Quizplus · Accepted Answer

The sequence is geometric with the first term $a = 4$ and common ratio $r = 3$. The sum of the first $n$ terms of a geometric sequence is given by $S_n = a \frac{r^n - 1}{r - 1}$. Here, $n = 11$ because the last term is $4 \cdot 3^{10}$. Calculating $S_{11} = 4 \frac{3^{11} - 1}{3 - 1} = 354,292$.

Use a Graphing Utility to Find the Sum of the Geometric