The 4th and 7th terms of a G.P. are and respectively. Find the sum of n terms of the G.P.

Nth term of GP is Tn = arn - 1


…(1)


Nth term of GP is Tn = arn - 1


…(2)


Divide (1) by (2)





Substituting in 1 we get


a = 1


Sum of GP for n terms =


a = 1, r = , n = n.





11