Q. 154.2( 139 Votes )

# If is the A.M. between a and b, then find the value of n.

Answer :

A.M. of a and b =

Given, is the A.M. between a and b.

(a + b) (an-1+ bn-1) = 2an + 2bn

an + abn-1 + ban-1 + bn = 2an + 2bn

abn-1 + ban-1 = an + bn

abn-1 – bn = an – ban-1

bn-1 (a – b) = an-1 (a – b)

n – 1 = 0

n = 1

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