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 ℝ-(a,b), then a2+b2 is equal to_____. [2026]
(90)
Let first three terms of G.P. are Ar, A, Ar
Ar·A·Ar=27
A3=27⇒A=3
3(1r+1+r)=3+3(r+1r)
We know, r+1r≥2 or r+1r≤-2
S∈ℝ-(-3,9)
a2+b2=9+81=90