Question

The following is a geometric sequence.
1, -2, 4, -8, 16,

Answer 1

multiply by -2

Answer 2

For the given sequence r = T2/T1 = -2/1 = -2
= T3/T2 = 4/-2 = -2
= T4/T3 = -8/4 = -2
The difference between the term is same.
The given sequence is in geometric progression.

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