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