Bi⁡(z)=12⁢π⁢∫-∞∞⁢ⅇπ⁢ⅈ/3exp⁡(13⁢t3-z⁢t)⁢ⅆ⁡t+12⁢π⁢∫-∞∞⁢ⅇ-π⁢ⅈ/3exp⁡(13⁢t3-z⁢t)⁢ⅆ⁡t.