SOLUTION: If the sum of the firstn terms of a G. P. is represented bySn, then prove that Sn (S3n –S2n) = (S2n –Sn)^2

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Question 1088869: If the sum of the firstn terms of a G. P. is represented bySn, then prove that
Sn (S3n –S2n) = (S2n –Sn)^2

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.
Actually, it is OBVIOUS.


HINT.  Each side is equal to  q%5E%282n%29%2AS%5Bn%5D%5E2,

       where q is the common ratio of the given progression.


On geometric progressions,  see the introductory lessons
    - Geometric progressions
    - The proofs of the formulas for geometric progressions
    - Problems on geometric progressions
    - Word problems on geometric progressions
in this site.

Also,  you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic
"Geometric progressions".