Intersection points Tangent line in a point of a non-degenerated conic section. The roots are h1 and h2. With these h-values correspond two intersection points with the conic section. These points can be coinciding or imaginary or ideal.
Previous theorem holds even if the line d is imaginary.
If a line and a conic section have more than two common points, the conic section is degenerated and the line is a component. Tangent line in a point of a non-degenerated conic section. A tangent line in a point D of a non-degenerated conic section is a line through D, such that the intersection points are coinciding. The previous equation has two coinciding roots for h. The other has to be 0.