## directrixThe line that, together with a point called the focus, serves to define a conic section as the locus of points whose distance from the focus is proportional to the horizontal distance from the directrix. If the ratio r = 1, the conic is a
parabola, if r < 1, it is an ellipse,
and if r > 1, it is a hyperbola.
## Related category• PLANE CURVES | |||||

Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact |