Q1 of 176 Page 20

If a, b, c are in G.P., prove that log a, log b, log c are in A.P.

If a, b, c are in GP


⇒ .....(i)


We know,


log a – log b = {property of logarithm}


and according to equation (i)


⇒


⇒ log b – log a = log c – log b


⇒ 2 log b = log a + log c {property of arithmetic mean}


Hence they are in AP. …proved


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