Conic sections {parabola, conic section} can have U shape.
equation
Parabola equation can be a * (x - h) = (y - k)^2, where h is x-intercept, k is y-intercept, and a is major conic-section diameter. Minor conic-section diameter is zero. For parabola, x = k - a. Parabola equation can be y = a*x^2 + b*x + c.
definition
Distance from any parabola point to parabola center {focus, parabola} equals distance from point to defining line {directrix, parabola}.
axis
A symmetry line {axis, parabola} divides parabolas lengthwise. Axis intersects parabola at point {vertex, parabola}. Distance {focal length, parabola} from focus to vertex is major diameter. Parabolas have no minor diameter.
semicubical parabola
Equation a * y^2 = x^3 or b * y^3 = x^2, where a is focal length, defines parabola {semicubical parabola}.
Mathematical Sciences>Geometry>Solid>Cone>Conic Section>Sections
3-Geometry-Solid-Cone-Conic Section-Sections
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Date Modified: 2022.0224