## Functions Modeling Change: A Preparation for Calculus, 5th Edition

In order for a sequence to be geometric, the quotient of all consecutive terms must be constant. Here: $\frac{a_2}{a_1}=\frac{1}{4}=0.25$ $\frac{a_3}{a_2}=\frac{1/4}{1}=0.25$ $\frac{a_4}{a_3}=\frac{1/8}{1/4}=0.5$ Thus we can see that the quotient is not constant, thus it is not a geometric sequence.