Hyperbolic CoTangent
Returns the hyperbolic cotangent of the given number.
NOTE: coth(x) = cosh(x) / sinh(x) = (ex + e-x) / (ex - e-x)
Returns the hyperbolic cotangent of the given number.
NOTE: coth(x) = cosh(x) / sinh(x) = (ex + e-x) / (ex - e-x)