(EllipticThetaPrime[1, 0, q] EllipticTheta[4, z, q])/ (4 EllipticTheta[2, 0, q] EllipticTheta[3, z, q]) == 1/4 + Sum[(-1)^n (q^n/(1 + q^(2 n))) Cos[2 n z], {n, 1, Infinity}] /; Abs[Im[z]] < (1/2) Im[\[Tau]] && q == E^(I Pi \[Tau])

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2001-10-29