Show that the products of the corresponding terms of the sequences a,ar,ar2,.......arn−1 and A,AR,AR2,....ARn−1 form a G.P and find the common ratio.
Multiplying the corresponding terms of the given sequences, we have :
(a×A),(ar×AR),(ar2×AR2),....(arn−1×ARn−1)
i.e. (aA),(aArR),(aAr2R2)....(aArn−1Rn−1)
Which is a G.P. having common ratio = aArRaA=rR