/// <summary>
/// A method to calculate the inverse value of the given vector.
/// </summary>
/// <param name="v">A vector.</param>
/// <returns>The inverse value of v: -v</returns>
public IVector2D <T> Inv(IVector2D <T> v)
{
return(new Vector2D <T>(Math.Inv(v.X),
Math.Inv(v.Y)));
}