23 Weierstrass Elliptic and Modular FunctionsWeierstrass Elliptic Functions

§23.12 Asymptotic Approximations

If q(=eπ⁢i⁢ω3/ω1)→0 with ω1 and z fixed, then

23.12.2 ζ⁡(z)=π24⁢ω12⁢(z3+2⁢ω1π⁢cot⁡(π⁢z2⁢ω1)−8⁢(z−ω1π⁢sin⁡(π⁢zω1))⁢q2+O⁡(q4)),
23.12.3 σ⁡(z)=2⁢ω1π⁢exp⁡(π2⁢z224⁢ω12)⁢sin⁡(π⁢z2⁢ω1)⁢(1−(π2⁢z2ω12−4⁢sin2⁡(π⁢z2⁢ω1))⁢q2+O⁡(q4)),

provided that z∉𝕃 in the case of (23.12.1) and (23.12.2). Also,

23.12.4 η1=π24⁢ω1⁢(13−8⁢q2+O⁡(q4)),

with similar results for η2 and η3 obtainable by use of (23.2.14).