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What is the sum of the first five terms of a geometric series with a1=6 and r= 1/3

User AChep
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1 Answer

4 votes

Answer: the sum of the first 5 terms is 8.96

Explanation:

In a geometric sequence, the consecutive terms differ by a common ratio. The formula for determining the sum of n terms, Sn of a geometric sequence is expressed as

Sn = a(1 - r^n)/(1 - r)

Where

n represents the number of term in the sequence.

a represents the first term in the sequence.

r represents the common ratio.

From the information given,

a = 6

r = 1/3

n = 5

Therefore, the sum of the first 5 terms, S5 is

S5 = 6(1 - 1/3^5)/(1 - 1/3)

S5 = 6(1 - 1/243)/(2/3)

S5 = 6(242/243)/(2/3)

S5 = (1452/243)/(2/3)

S5 = (1452/243) Ă— (3/2)

S5 = 4356/486

S5 = 8.96

User Openmobster
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6.3k points
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