An ellipse forms by the locus of points in a plane, but only when the sum of the distances form two fixed points, called foci (plural for focus), is constant. An ellipse results when an oblique plane cuts a cone, without intersecting the base.
Distance from focus to focus equals the distance frmo 1 point to one focus, plus the distance from some point to the second focus.
The Major Axis is a segment tht contains the function of an ellipse andn has end ponts on the ellipse.
Center: (h,k) It is also the midpoint of the major axis and the minor axis and the midpoint from the two vertex or the two Co-Vertex.
The segment from the center to each Vertex are congruent and the segment from the center to each Co-Vertex are also congruent.
- The distance from each Vertex to the Center is represented by a units.
- The distance from the Center to each Co-Vertex is b units.
- And the distance from the Center to each Focus is c units.
How to graph an ellipse
Video showing how to Graph Ellipses
Video 2 on how to Graph Ellipses
The Conic Club 