Question

Is the sequence 4, 16, 28, 40, … geometric? If so find the common ratio. If not, explain why.

Answer 1

Consider the given sequence,

4, 16, 28, 40, …

 

Find the ratio of second term and first term,

a2/a1 = 16/4

           = 4

 

Find the ratio of third term and second term,

a3/a2 = 28/16

           = 1.75

 

Find the ratio of forth term and third term,

a4/a3 = 40/28

           = 1.428571

As the ratio of any two successive terms is not constant, the given series is “Not a Geometric Sequence.”

As the ratio of any two successive terms is not constant, the given series is “Not a Geometric Sequence.”