directrix
Parabola's defining line
A directrix is a fixed line used in defining a conic section.
For a parabola, every point on the curve is equidistant from the directrix and a fixed point called the focus.
Ellipses and hyperbolas also have directrices, though their geometric relationships are more complex.
The term belongs almost exclusively to mathematics.
Concentrated attention point
- eccentricityUnconventional behavior or nature
- parabolaSymmetrical open plane curve
- ellipseConic section curve
- hyperbolaCurve with two branches
vertex · axis · locus · curve · perpendicular · distance · ratio · fixed-line
Concentrated attention point
- fociCentral points of convergence
- eccentricityUnconventional behavior or nature
- axisRotation reference line
- ovalElongated rounded shape
perihelion · aphelion · centroid · tangent
Concentrated attention point
- fociCentral points of convergence
- eccentricityUnconventional behavior or nature
- asymptoteUnreached bounding curve
- branchDivision or woody limb
rectangular · unbounded · navigation · LORAN
Concentrated attention point
- vertexPoint where edges converge
- equidistantEqually far from each
- reflectionReturned light or thought
- quadraticInvolving squared terms
curve · opening · concave · tangent · normal · perpendicular · graph · coefficient
Line-drawing tool
- rulerOne who governs
- blueprintDetailed technical drawing
- CADTechnical drawing technology
- compassDevice showing cardinal directions
protractor · template · specification · layout · architectural
focus
Concentrated attention point
- eccentricityUnconventional behavior or nature
- parabolaSymmetrical open plane curve
- ellipseConic section curve
hyperbola · vertex · axis · locus · curve · perpendicular · distance · ratio · fixed-line · quadratic
focus
Concentrated attention point
- fociCentral points of convergence
- eccentricityUnconventional behavior or nature
- axisRotation reference line
oval · perihelion · aphelion · centroid · tangent
focus
Concentrated attention point
- fociCentral points of convergence
- eccentricityUnconventional behavior or nature
- asymptoteUnreached bounding curve
branch · rectangular · unbounded · navigation · LORAN
focus
Concentrated attention point
- vertexPoint where edges converge
- equidistantEqually far from each
- reflectionReturned light or thought
quadratic · curve · opening · concave · tangent · normal · perpendicular · graph · coefficient · intercept
straightedge
Line-drawing tool
compass · protractor · template · specification · layout · architectural
- linesstraight line, line, dotted line, dashed line, solid line
- conic sectionsellipse, parabola, hyperbola, circle, conic section
- polynomialspolynomial, polynomials, binomial, monomial, binomials
- geometryangles, circles, angle, shapes, lines
- coordinate geometrycoordinate, coordinates, coordinate plane, coordinate grid, Cartesian plane
- ruled surfacescone, cylinder, plane, hyperboloid, helicoid