If x^2, b^2, y^2 are in AP, a, x, b and b, y, c both are in GP, prove that a, b, c are in AP.
Let a and b be two unequal positive numbers. Then,
A.M. = (a+b)/2 G.M = (ab)
and, H.M. = 2ab/(a+b) To Prove the first part, we have
(A.M.) x (G.M.) = (a+b)/2 x 2ab/(a+b)
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