public static void XatY(double yCoord, double x, double y, double rotation, double xCoordExpected)
        {
            CartesianCoordinate center = new CartesianCoordinate(x, y);
            EllipticalCurve     curve  = new EllipticalCurve(a, b, center, rotation, Tolerance);

            double xCoord = curve.XatY(yCoord);

            Assert.AreEqual(xCoordExpected, xCoord, Tolerance);
        }
        public static void XatY_Out_of_Range_Return_Infinity(double yCoord, double x, double y, double rotation)
        {
            CartesianCoordinate center = new CartesianCoordinate(x, y);
            EllipticalCurve     curve  = new EllipticalCurve(a, b, center, rotation, Tolerance);

            double xCoord = curve.XatY(yCoord);

            Assert.AreEqual(double.PositiveInfinity, xCoord);
        }