Assertion: ellipse's distance | /r/HasProperty | fixed line
Facets:
value: at infinity
type: OTHER
Source sentences:
text: If the distance to the focus is fixed and the directrix is a line at infinity, so the eccentricity is zero, then the conic is a circle.
text: The distance from the center to a vertex is the fixed value a .
text: The distance from the center to either focus is the fixed value c .
text: A conic is defined as the locus of points for each of which the distance to the focus divided by the distance to the directrix is a fixed positive constant, called the eccentricity e.