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Answered

Which of the following sequences are geometric sequences?


Check all that apply.

A10, 13, 16.9, 21.97, 28.561, 37.1293, ...
B10, 12, 13.1, 13.31, 15.641, ...
C15, 30, 60, 120, 240, ...
D0.1, 0.01, 0.001, 0.0001, 0.00001, ...
E5, 125, 225, 1,625, 3,125, ...

Verified Answer :

HomertheGenius

Geometric sequence: a ( n ) = a ( n - 1 ) · r
A ) 13 = 10 · r,  r = 1.3
16.9 = 13 · 1.3,  21.97 = 16.9 · 1.3,  28.561 = 21.97 · 1.3,  
37.1293 = 28.561 · 1.3 
C ) 30 = 15 · r,  r = 2, 60 = 30 · 2,  120 = 60 · 2,  240 = 120 · 2 
D ) 0.01 = 0.1 · r,   r = 0.1
0.001 = 0.01 · 0.1 ,   0.0001 = 0.001 · 0.01,  0.00001 = 0.0001 · 0.1
Answer: Geometric sequence are A ), C ) and D ).

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