h2⁢s⁡(θ,α)=ⅇⅈ⁢α⁢(π-θ)1+ⅇ-ⅈ⁢θ⁢a2⁢s⁡(θ,α)+(-1)s-1⁢ⅈ⁢1⋅3⋅5⁢⋯⁢(2⁢s-1)(c⁡(θ))2⁢s+1,