z⁢(1-z)⁢I⁡(∫∞wⅆ⁡tt⁢(t-1)⁢(t-z))=w⁡(w-1)⁢(w-z)⁢(α+β⁢zw2+γ⁢(z-1)(w-1)2+(δ-12)⁢z⁢(z-1)(w-z)2),