Bi′⁡z=z/3⁢I2/3⁡ζ+I-2/3⁡ζ=12⁢z/3⁢ⅇπ⁢ⅈ/3⁢H2/31⁡ζ⁢ⅇ-π⁢ⅈ/2+ⅇ-π⁢ⅈ/3⁢H2/32⁡ζ⁢ⅇπ⁢ⅈ/2=12⁢z/3⁢ⅇ-π⁢ⅈ/3⁢H-2/31⁡ζ⁢ⅇ-π⁢ⅈ/2+ⅇπ⁢ⅈ/3⁢H-2/32⁡ζ⁢ⅇπ⁢ⅈ/2,