ⅇ-b⁢π⁢ⅈ⁢Γ⁡(1-b)2⁢π⁢ⅈ⁢Γ⁡(c-b)⁢∫1(0+)tb-1⁢(1-t)c-b-1(1-z⁢t)a⁢ⅆ⁡t,