20 Theta FunctionsProperties

§20.4 Values at z = 0

Contents
  1. §20.4(i) Functions and First Derivatives
  2. §20.4(ii) Higher Derivatives

§20.4(i) Functions and First Derivatives

20.4.1 θ1⁡(0,q)=θ2′⁡(0,q)=θ3′⁡(0,q)=θ4′⁡(0,q)=0,
20.4.2 θ1′⁡(0,q) =2⁢q1/4⁢∏n=1∞(1−q2⁢n)3=2⁢q1/4⁢(q2;q2)∞3,
20.4.3 θ2⁡(0,q) =2⁢q1/4⁢∏n=1∞(1−q2⁢n)⁢(1+q2⁢n)2,
20.4.4 θ3⁡(0,q) =∏n=1∞(1−q2⁢n)⁢(1+q2⁢n−1)2,
20.4.5 θ4⁡(0,q) =∏n=1∞(1−q2⁢n)⁢(1−q2⁢n−1)2.

Jacobi’s Identity

20.4.6 θ1′⁡(0,q)=θ2⁡(0,q)⁢θ3⁡(0,q)⁢θ4⁡(0,q).

§20.4(ii) Higher Derivatives

20.4.7 θ1′′⁡(0,q)=θ2′′′⁡(0,q)=θ3′′′⁡(0,q)=θ4′′′⁡(0,q)=0.
20.4.8 θ1′′′⁡(0,q)θ1′⁡(0,q) =−1+24⁢∑n=1∞q2⁢n(1−q2⁢n)2.
20.4.9 θ2′′⁡(0,q)θ2⁡(0,q) =−1−8⁢∑n=1∞q2⁢n(1+q2⁢n)2,
20.4.10 θ3′′⁡(0,q)θ3⁡(0,q) =−8⁢∑n=1∞q2⁢n−1(1+q2⁢n−1)2,
20.4.11 θ4′′⁡(0,q)θ4⁡(0,q) =8⁢∑n=1∞q2⁢n−1(1−q2⁢n−1)2.
20.4.12 θ1′′′⁡(0,q)θ1′⁡(0,q)=θ2′′⁡(0,q)θ2⁡(0,q)+θ3′′⁡(0,q)θ3⁡(0,q)+θ4′′⁡(0,q)θ4⁡(0,q).