/// <summary>Trigonometric Hyperbolic Secant (sech, Secans hyperbolicus) of this <c>Complex</c>.</summary>
public Complex HyperbolicSecant()
{
if (IsReal)
{
return(new Complex(Trig.HyperbolicSecant(real), 0d));
}
Complex exp = this.Exponential();
return(2 * exp / (exp.Square() + 1));
}
