Tanh[z] == (-I) Sqrt[Sech[z]^2 - 1] (-1)^Floor[-((2 Im[z])/Pi)] (1 - (1 + (-1)^(Floor[-(Im[z]/Pi)] + Floor[Im[z]/Pi])) UnitStep[-Re[z]]) (1 - (1 + (-1)^(Floor[1/2 - Im[z]/Pi] + Floor[-(1/2) + Im[z]/Pi])) UnitStep[Re[z]])

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2001-10-29