Set of points on a plane from which no tangents can be drawn to a conic section.
Example
The orange portion of the graph below illustrates the interior of a hyperbola with the equation \(\dfrac{x^2}{4} − \dfrac{y^2}{7} = 1\), that is, the region determined by the inequality \(\dfrac{x^2}{4} − \dfrac{y^2}{7} ≥ 1\).
