SOLUTION: Use the formula for the sum of the first n terms of a geometric sequence to solve. Find the sum of the first six terms of the geometric sequence: 3, 12, 48, . . . . a. 63 b.

Algebra ->  Sequences-and-series -> SOLUTION: Use the formula for the sum of the first n terms of a geometric sequence to solve. Find the sum of the first six terms of the geometric sequence: 3, 12, 48, . . . . a. 63 b.      Log On


   

Question 1181056: Use the formula for the sum of the first n terms of a geometric sequence to solve.
Find the sum of the first six terms of the geometric sequence: 3, 12, 48, . . . .
a. 63
b. 971
c. 4095
d. 1365
Answer by MathLover1(20850) About Me  (Show Source):
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the sum of the first six terms of the geometric sequence: 3, 12, 48
find+r
+r=12%2F3=4
For r≠1, the sum of the first n terms of a geometric series is given by the formula
s=a%281-r%5En%29%2F%281-r%29
if a=3, r=4, and n=6
s=3%281-4%5E6%29%2F%281-4%29
s=3%28-4095%29%2F%28-3%29
s=%28-4095%29%2F%28-1%29
s=4095

answer: c. 4095