<PRE><B>Question 909853</B>
Which one of the following is a geometric sequence?
 A. 2,–3, 9&amp;#8260;2, &amp;#8722;18&amp;#8260;4
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Testing for &quot;r&quot;:: -3/2 = -1.5 ; (9/2)/-3 = -3/2 ; (-18/4)/(9/2) = -2
Ans: inconsistent &quot;r&quot; ; so not geometric
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 B. 0, 1, 2, 3, . . .
Testing for &quot;r&quot;:: 1/0 = undefined
Ans: undefined &quot;r&quot;:: so not geometric
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 C. 8, 4, 2, 1, 1&amp;#8260;2, 1&amp;#8260;4, . . .
Testing shows r = 1/2 ; so it is geometric
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 D. –7, 10, 23, 36, . . .
Testing:: 10/-7 ; 23/10 ; 36/23
Ans: inconsistent &quot;r&quot;: so not geometric
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Cheers,
Stan H.
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