Q.

In a G.P., if the product of the first three terms is 27 and the set of all possible values for the sum of its first three terms is -(a,b), then a2+b2 is equal to_____. [2026]


Ans.

(90)

Let first three terms of G.P. are Ar, A, Ar

Ar·A·Ar=27

A3=27A=3

3(1r+1+r)=3+3(r+1r)

We know, r+1r2 or r+1r-2

S-(-3,9)

a2+b2=9+81=90