Jacobi zeta function
In mathematics, the Jacobi zeta function Z(u) is the logarithmic derivative of the Jacobi theta function Θ(u). It is also commonly denoted as zn ( u , k ) {\displaystyle \operatorname {zn} (u,k)} Θ ( u ) = Θ 4 ( π u 2 K ) {\displaystyle \Theta (u)=\Theta _{4}\left({\frac {\pi u}{2K}}\right)} Z ( u ) = ∂ ∂ u ln Θ ( u ) {\displaystyle Z(u)={\frac {\partial }{\partial u}}\ln \Theta (u)} = Θ ′ ( u ) Θ ( u ) {\displaystyle ={\frac {\Theta '(u)}{\Theta (u)}}} Z ( ϕ | m ) = E ( ϕ | m ) − E ( m ) K ( m ) F ( ϕ | m ) {\displaystyle Z(\phi |m)=E(\phi |m)-{\frac {E(m)}{K(m)}}F(\phi |m)} Where E, K, and F are generic Incomplete Elliptical Integrals of the first and second kind.