/// <summary>
/// Returns the cosine of the specified complex function argument z.
/// </summary>
/// <param name="z">Function argument.</param>
/// <returns>The cosine of the specified complex function argument z.</returns>
public static ComplexFloat Cos(ComplexFloat z)
{
double ezi = Math.Exp(z.Im);
double inv = 1.0 / ezi;
return(ComplexFloat.FromRealImaginary((float)(0.5 * Math.Cos(z.Re) * (inv + ezi)), (float)(0.5 * Math.Sin(z.Re) * (inv - ezi))));
}
/// <summary>
/// Returns the tangent of the specified complex function argument z.
/// </summary>
/// <param name="z">Function argument.</param>
/// <returns>The tangent of the specified complex function argument z.</returns>
public static ComplexFloat Tan(ComplexFloat z)
{
double sinzr = Math.Sin(z.Re);
double coszr = Math.Cos(z.Re);
double ezi = Math.Exp(z.Im);
double inv = 1.0 / ezi;
double ediff = inv - ezi;
double esum = inv + ezi;
return(ComplexFloat.FromRealImaginary((float)(4 * sinzr * coszr), (float)(-ediff * esum)) / (float)(square(coszr * esum) + square(sinzr * ediff)));
}