Find the indicated sum. Use the formula for the sum of the first n terms of a geometric sequence.
-$$\sum _ { i = 1 } ^ { 5 } 4 \cdot 3 i$$
A) 1452
B) 2460
C) 93
D) 480

Question

Quizplus · Accepted Answer

The sum of the first n terms of a geometric sequence is given by the formula $$S_n = a\frac{1-r^n}{1-r}$$ where a is the first term, r is the common ratio, and n is the number of terms. In this case, a = 4, r = 3, and n = 5. So, the sum of the first 5 terms is $$S_5 = 4\frac{1-3^5}{1-3} = 4\frac{1-243}{-2} = 4\frac{-242}{-2} = 484$$

Find the Indicated Sum ∑i=154⋅3i\sum _ { i = 1 } ^ { 5 } 4 \cdot 3 ii=1∑5​4⋅3i

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