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Notes 8.1 Conics Sections – The Parabola. I. Introduction. A.) A conic section is the intersection of a plane and a cone . B.) By changing the angle and the location of intersection, a parabola, ellipse, hyperbola, circle, point, line, or a pair of intersecting lines is produced.
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I. Introduction A.) A conic section is the intersection of a plane and a cone. B.) By changing the angle and the location of intersection, a parabola, ellipse, hyperbola, circle, point, line, or a pair of intersecting lines is produced.
C.) Standard Conics: 1.) Parabola 2.) Ellipse 3.) Hyperbola
D.) Degenerate Conics 1.) Circle 2.) Point 3.) Line 4.) Intersecting Lines
E.) Forming a Parabola – When a plane intersects a double-napped cone and is parallel to the side of the cone, a parabola is formed.
F.) General Form Equation for All Conics If both B and C = 0, or A and B = 0, the conic is a parabola
II. The Parabola A.) In general - A parabola is the graph of a quadratic equation, or any equation in the form of
B.) Def. - A PARABOLA is the set of all points in a plane equidistant from a particular line (the DIRECTRIX) and a particular point (the FOCUS) in the plane.
Axis of Symmetry Focus Focal Width Vertex Focal Length Directrix
C.) Parabolas (Vertex = (0,0)) Standard Form Focus Directrix Axis of Symmetry Focal Length Focal Width
D.) Ex. 1- Find the focus, directrix, and focal width of the parabola y = 2x2. Focus = Directrix = Focal Width =
E.) Ex. 2- Do the same for the parabola Focus = Directrix = Focal Width =
F.) Ex. 3- Find the equation of a parabola with a directrix of x = -3 and a focus of (3, 0).
G.) Parabolas (Vertex = (h, k)) St. Fm. Focus Directrix Ax. of Sym. Fo. Lgth. Fo. Wth.
H.) Ex. 4- Find the standard form equation for the parabola with a vertex of (4, 7) and a focus of (4, 3).
I.) Ex. 5- Find the vertex, focus, and directrix of the parabola 0 = x2 – 2x – 3y – 5. focus = Directrix = vertex =
III. Paraboloids of Revolution A.) A PARABOLOID is a 3-dimensional solids created by revolving a parabola about an axis. Examples of these include headlights, flashlights, microphones, and satellites.
B.) Ex. 6– A searchlight is in the shape of a paraboloid of revolution. If the light is 2 feet across and 1 ½ feet deep, where should the bulb be placed to maximize the amount of light emitted?
The bulb should be placed 2” from the vertex of the paraboloid