Wolfram Research
Wolfram Mathworld: Conic Section Directrix
Explains how the directrix relates to the three conic sections: parabola, ellipse, and hyperbola. Includes a definition, formulas, and links to related topics.
Wolfram Research
Wolfram Math World: Conic Sections
A fairly comprehensive look at various types of conic sections is presented. Most of the information is presented as introductory, with an emphasis on terminology. Through an understanding of the terminology, one can understand the...
Johan Claeys
Math Abundance: The Parabola
Defines parabolas, their properties, gives parametric equations, tangent line in a point D of a parabola, etc.
Discovery Education
Discovery Education: Web Math: Plots and Geometry
This site provides descriptions and helpful hints regarding conic sections - circles, parabolas, ellipses, and hyperbolas. Content also includes interactive problem solvers complete with a full analysis of the math behind the answer.
Discovery Education
Discovery Education: Web Math: Graphing Hyperbolas
WebMath offers a java applet that allows you to input information about hyperbolas in one of eight forms and gives you the graph of the hyperbola.
Varsity Tutors
Varsity Tutors: Hotmath: Conic Sections
Students can investigate the graphs of conic sections in standard form. Cirlce, ellipse, and hyperbola graphs are included.
Varsity Tutors
Varsity Tutors: Hotmath: General Form for Conic Sections
Students investigate the general form of the equation for a conic section. This interactive tool evaluates the changes that occur from using different coefficients in the equation.
CK-12 Foundation
Ck 12: Analysis: Parabolas and Analytic Geometry
[Free Registration/Login may be required to access all resource tools.] In this lesson students gain an understanding of parabolas using analytic geometry, by exploring guided notes, watching a video and attempting practice problems.
Math Is Fun
Math Is Fun: Conic Sections
Students learn about conic sections. Topics include eccentricity, directrix, and the general equation. The tutorial consists of notes, examples, and practice problems to check for comprehension.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Parabola Equation
Dr. Math, in a reply to a student's question, describes how to obtain the equation of a parabola.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Graphing Parabolas
Dr. Math helps a student with the plotting and with finding the vertex and line of symmetry of a parabola.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Parabola
Dr. Math, in a reply to a student's question, explains how to find the location of the vertex and focus, calculate the distance between the focus and vertex, as well as identify the axis of symmetry and the directix.
Analyze Math
Analyze Math: Equation of Hyperbola: Graphing Problems
Learners investigate the hyperbola equation. The tutorial examines intercepts, foci, and sketching hypberbolas. Examples with detailed solutions are included.
Johan Claeys
Math Abundance: The Hyperbola
Great Site! Defines Hyperbola, gives the parametric equation, etc.
Purple Math
Purplemath: Completing the Square: Ellipses Equations
Demonstrates step-by-step how to complete the square for ellipses and hyperbolas. Includes several charts and graphs for understanding.
Purple Math
Purplemath: Completing the Square: Finding the Vertex
Demonstrates step-by-step how to complete the square to find the vertex of a parabola. Thorough descriptions of each problem.
Purple Math
Purplemath: Conics: Ellipses: Introduction
Introduces the basic terms, variables, and equations for ellipses, and discusses their physical properties.
Purple Math
Purplemath: Conics: An Overview
Introduces the basics of conics in algebra, including a flow-chart for determining which sort of conic is represented by a given equation.
Other
Math Pages: Parabola Through Four Points
This resource explains how a parabola is found through four points. There are diagrams to go along with the information.
Illustrative Mathematics
Illustrative Mathematics: G Gpe Defining Parabolas Geometrically
The purpose of this task is to show that the points on a parabola can be characterized by being equidistant from a point (the focus) and a line (the directrix). Aligns with HSG-GPE.A.2.
Purple Math
Purplemath: Conics: Parabolas: Introduction
This reference material introduces the terms and equations related to parabolas in the context of conics. Also, relates concepts to previously-learned material and shows how to 'read' from the 'conics' form of the parabola equation.
Khan Academy
Khan Academy: Equation of a Parabola From Focus and Directrix
Given the focus and the directrix of a parabola, find its equation. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Other
Gobierno De Navarra: Estudio De Las Conicas
Learn about conics sections with these interactive activities.
Alabama Learning Exchange
Alex: Conic Sections: Playing With Parabolas
Through a mixture of online exploration, and teacher instruction, students will discover how parabolas are formed and will be able to use the key components from a graph (vertex, focus and directrix,) to generate the equation of a graph.