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Fungrim entry: 561d75

d2dz2log ⁣(θ2 ⁣(z,τ))=π2n=1cos2 ⁣(π(z+nτ))\frac{d^{2}}{{d z}^{2}} \log\!\left(\theta_{2}\!\left(z , \tau\right)\right) = {\pi}^{2} \sum_{n=-\infty}^{\infty} \frac{1}{\cos^{2}\!\left(\pi \left(z + n \tau\right)\right)}
Assumptions:zC  and  τH  and  θ2 ⁣(z,τ)0z \in \mathbb{C} \;\mathbin{\operatorname{and}}\; \tau \in \mathbb{H} \;\mathbin{\operatorname{and}}\; \theta_{2}\!\left(z , \tau\right) \ne 0
TeX:
\frac{d^{2}}{{d z}^{2}} \log\!\left(\theta_{2}\!\left(z , \tau\right)\right) = {\pi}^{2} \sum_{n=-\infty}^{\infty} \frac{1}{\cos^{2}\!\left(\pi \left(z + n \tau\right)\right)}

z \in \mathbb{C} \;\mathbin{\operatorname{and}}\; \tau \in \mathbb{H} \;\mathbin{\operatorname{and}}\; \theta_{2}\!\left(z , \tau\right) \ne 0
Definitions:
Fungrim symbol Notation Short description
ComplexBranchDerivativeddzf ⁣(z)\frac{d}{d z}\, f\!\left(z\right) Complex derivative, allowing branch cuts
Loglog(z)\log(z) Natural logarithm
JacobiThetaθj ⁣(z,τ)\theta_{j}\!\left(z , \tau\right) Jacobi theta function
Powab{a}^{b} Power
Piπ\pi The constant pi (3.14...)
Sumnf(n)\sum_{n} f(n) Sum
Coscos(z)\cos(z) Cosine
Infinity\infty Positive infinity
CCC\mathbb{C} Complex numbers
HHH\mathbb{H} Upper complex half-plane
Source code for this entry:
Entry(ID("561d75"),
    Formula(Equal(ComplexBranchDerivative(Log(JacobiTheta(2, z, tau)), For(z, z, 2)), Mul(Pow(Pi, 2), Sum(Div(1, Pow(Cos(Mul(Pi, Add(z, Mul(n, tau)))), 2)), For(n, Neg(Infinity), Infinity))))),
    Variables(z, tau),
    Assumptions(And(Element(z, CC), Element(tau, HH), NotEqual(JacobiTheta(2, z, tau), 0))))

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2020-08-27 09:56:25.682319 UTC