If Arithmetic Mean of 1st k terms of Arithmetic Progression with 1st term a and common difference d is equal to the Geometric Mean of 1st k terms of Geometric Progression with 1st term a and common ratio r, then find the range of r for which a≈2d/(r-1).

Think of binomial thoerem, once u derived the  expression
for a. :)

Posted by Praneeth on 2008-01-25 06:36:14