Wolfram Research
Wolfram Math World: Eccentricity
This site explains eccentricity, the quantity defined by a conic section to determine its type of conic section. Has links to related topics.
Wolfram Research
Wolfram Math World: Focus
An explanation for the focus in conic sections along with diagrams. Site provides graphs, references, and a brief bibliography and citation.
National Council of Teachers of Mathematics
The Math Forum: Conic Basics
A written description of the different conic sections is described at this site from the Math Forum. The description identifies the importance of the eccentricity in determining the type of conic.
National Council of Teachers of Mathematics
The Math Forum: Everyday Appearances of Conics
Just getting started with conics and you need some examples of where they occur? Check out Dr. Math's reply to such a question.
Math Words
Math words.com: Hyperbola
A definition for what a hyperbola is along with example diagrams of what horizontal and vertical hyperbolas are and gives the standard form equation.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Equations of Conics
Posed with a student question about equations of conics, Dr. Math provides some insight on the standard form of parabolas, ellipses, and hyperbolas. One example is shown.
Math Open Reference
Math Open Reference: Parabola
Learn about the three ways to define a parabola: Focus and Directrix, The Graph of a Function, and As a Conic Section. Examples are provided.
Curated OER
Math World: Hyperbola
This site contains a vast amount of information relating to the hyperbola, including the definition of a hyperbola, equations in various systems, including polar, and many important characteristics of hyperbolas. Site also provides many...