Show that the ratio of the sum of first n terms of a G.P. to the sum of terms from (n + 1)th to (2n)th term is 
First n terms of GP be a, ar, ar2…, arn - 1
From n + 1 term,
GP = arn, arn + 1, …, ar2n - 1
Sum of GP for n terms S1 = 
Sum of GP for next terms S2 = 
∴ 
⇒ 
⇒ 
Hence, Proved.
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