- Poinsot's spirals
In

mathematics ,**Poinsot's spirals**are twospiral s represented by thepolar equation s:$r=a,operatorname\{csch\}(n\; heta)$:$r=a,operatorname\{sech\}(n\; heta)$where csch is thehyperbolic cosecant , and sech is thehyperbolic secant .

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