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