Geometric sequences are:
-1, 2.5, -6.25, 15,625,...
8, 0.8, 0.08, 0.008,...
Geometric sequence is a sequence of numbers term after the first term is found by multiplying the previous term by a common ratio --a fixed, none-zero number.
-1 * -2.5 = 2.5
2.5 * -2.5 = -6.25
-6.25 * -2.5 = 15.625
8 * 0.10 = 0.8
0.8 * 0.10 = 0.08
0.08 * 0.10 = 0.008