2⁢ⅈ⁢K⁢dn⁡(2⁢K⁢t,k)=limN→∞⁡∑n=-NN(-1)n⁢πtan⁡(π⁢(t-(n+12)⁢τ))=limN→∞⁡∑n=-NN(-1)n⁢(limM→∞⁡∑m=-MM1t-m-(n+12)⁢τ).