/// <summary>Trigonometric Hyperbolic Cotangent (Cotangens hyperbolicus) of this <c>Complex</c>.</summary>
public Complex Coth()
{
if (IsReal)
{
return(new Complex(Trig.Coth(real), 0d));
}
double sini = Trig.Sin(imag);
double sinhr = Trig.Sinh(real);
double denom = sini * sini + sinhr * sinhr;
return(new Complex(sinhr * Trig.Cosh(real) / denom, sini * Trig.Cos(imag) / denom));
}
