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The General Equation for a Conic Section: Ax2 + Bxy + Cy2 + Dx + Ey + F = 0 | The type of section can be found from the sign of: B2 - 4AC | If B2 - 4AC is... | then the curve is a... | | < 0 | ellipse, circle, point or no curve. | | = 0 | parabola, 2 parallel lines, 1 line or no curve. | | > 0 | hyperbola or 2 intersecting lines. | The Conic Sections. For any of the below with a center (j, k) instead of (0, 0), replace each x term with (x-j) and each y term with (y-k). | | Circle | Ellipse | Parabola | Hyperbola | | Equation (horiz. vertex): | x2 + y2 = r2 | x2 / a2 + y2 / b2 = 1 | 4px = y2 | x2 / a2 - y2 / b2 = 1 | | Equations of Asymptotes: | | | | y = ± (b/a)x | | Equation (vert. vertex): | x2 + y2 = r2 | y2 / a2 + x2 / b2 = 1 | 4py = x2 | y2 / a2 - x2 / b2 = 1 | | Equations of Asymptotes: | | | | x = ± (b/a)y | | Variables: | r = circle radius | a = major radius (= 1/2 length major axis) b = minor radius (= 1/2 length minor axis) c = distance center to focus | p = distance from vertex to focus (or directrix) | a = 1/2 length major axis b = 1/2 length minor axis c = distance center to focus | | Eccentricity: | 0 | c/a | 1 | c/a | | Relation to Focus: | p = 0 | a2 - b2 = c2 | p = p | a2 + b2 = c2 | | Definition: is the locus of all points which meet the condition... | distance to the origin is constant | sum of distances to each focus is constant | distance to focus = distance to directrix | difference between distances to each foci is constant | | Related Topics: | GEOMETRIC CONIC SECTION | | | |
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