Find the indicated sum. Use the formula for the sum of the first n terms of a geometric sequence.
-$$\sum _ { i = 1 } ^ { 5 } 3 \cdot 4 i$$
A) 4092
B) 7710
C) 268
D) 252

Question

Quizplus · Accepted Answer

The given series is a geometric series with the first term $ a = 12 $ and common ratio $ r = 4 $. The sum of the first $ n $ terms of a geometric series is given by $ S_n = a \frac{r^n - 1}{r - 1} $. For $ n = 5 $, the sum is $ S_5 = 12 \frac{4^5 - 1}{4 - 1} = 12 \times \frac{1024 - 1}{3} = 12 \times 341 = 4092 $.

Find the Indicated Sum ∑i=153⋅4i\sum _ { i = 1 } ^ { 5 } 3 \cdot 4 ii=1∑5​3⋅4i

Find the Indicated Sum $\sum _ { i = 1 } ^ { 5 } 3 \cdot 4 i$