Sea δ=ϵ2/5\delta=\epsilon^2 /5δ=ϵ2/5. Si 5−ϵ2<x<55-\epsilon^2 < x < 55−ϵ2<x<5, entonces ∣5−x∣=5−x<ϵ|\sqrt{5-x}|=\sqrt{5-x} <\epsilon∣5−x∣=5−x<ϵ.