In a G.P. 729, 243, 81,… find t7 .
In a G.P. 729, 243, 81,… find t7 .
Solution :
tn = ar n -1
a = 729, r = 243/729 = 1/3 and n = 7
t7 = (729) (1/3)7 -1
= (729) (1/3)6
t7 = 1
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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.