Key Concepts & Glossary
Key Concepts
- Any conic may be determined by a single focus, the corresponding eccentricity, and the directrix. We can also define a conic in terms of a fixed point, the focus at the pole, and a line, the directrix, which is perpendicular to the polar axis.
- A conic is the set of all points , where eccentricity is a positive real number. Each conic may be written in terms of its polar equation.
- The polar equations of conics can be graphed.
- Conics can be defined in terms of a focus, a directrix, and eccentricity.
- We can use the identities , and to convert the equation for a conic from polar to rectangular form.
Glossary
- eccentricity
- the ratio of the distances from a point on the graph to the focus and to the directrix represented by , where is a positive real number
- polar equation
- an equation of a curve in polar coordinates and