Let α,β be real and z be a complex number. If z2+αz+β=0 has two distinct roots on the line Re(z) = 1, then it is necessary that
β ϵ (1,∞)
Let the roots of the given equation be 1+ip and 1−ip, p ϵ R, p≠0⇒β=product of roots=(1+ip)(1−ip)=1+p2>1, ∀ p ϵ R⇒β ϵ (1,∞)