Which of the following sequences are in G.P.? (i) 3, 9, 27, 81,…

Which of the following sequences are in G.P.?

(i) 3, 9, 27, 81,…

Solution :

First term (a)  = 3, common ratio

r  = t2/t1   =  9/3 r = 3

r  = t3/t2   =  27/9 r = 3

r  = t2/t1   =  81/27 r = 3

Since the common ratios are the same, it is a geometric sequence.