SOLUTION: if the first term of a geometric sequence is 3/2 and the second and third terms are -3/4 and 3/8, respectively, which of the following represents the nth term of the sequence?

Question 391759: if the first term of a geometric sequence is 3/2 and the second and third terms are -3/4 and 3/8, respectively, which of the following represents the nth term of the sequence?
a) 3(-1)^n-1/2n
b) 3(-1)^n/2n
c) 3(-1)^n-1/2^n
d) 3(-1)^n/2^n
e) 3(-1)^n-1/2^n+1
please provide explanation!
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
if the first term of a geometric sequence is 3/2 and the second and third terms are -3/4 and 3/8, respectively, which of the following represents the nth term of the sequence?
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A geometric sequence has a common ratio between consecutive terms.
r = (-3/4)/(3/2) = -1/2
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a(n) = ar^(n-1) = (3/2)(-1/2)^(n-1)
a(n) = 3*(-1)^(n-1)/2^(n)
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Ans: c
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Cheers,
Stan H.
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a) 3(-1)^n-1/2n
b) 3(-1)^n/2n
c) 3(-1)^n-1/2^n
d) 3(-1)^n/2^n
e) 3(-1)^n-1/2^n+1

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