public void Test_Coth()
{
Complex r = new Complex(Math.Log(3), 0);
Complex i = new Complex(0, Math.PI / 4);
Complex c = new Complex(Math.Log(3), Math.PI / 2);
Assert.IsTrue(AreApproximatelyEqual(Elementary.Coth(r).Real, 1.25D));
Assert.IsTrue(IsApproximatelyZero(Elementary.Coth(r).Imaginary));
Assert.IsTrue(IsApproximatelyZero(Elementary.Coth(i).Real));
Assert.IsTrue(AreApproximatelyEqual(Elementary.Coth(i).Imaginary, -1D));
Assert.IsTrue(IsApproximatelyZero(Elementary.Coth(c).Imaginary));
Assert.IsTrue(AreApproximatelyEqual(Elementary.Coth(c).Real, 4D / 5D));
}