For what values of the constant \(k\) is this conic section an ellipse? Now assume that \(k\) has the value in the middle of the interval found in part (a). Determine the location of the focus and ...

Geometrical Conic Sections: an Elementary Treatise, in which the Conic Sections are defined as the Plane Sections of a Cone, and treated by the Method of Projections. By J. Stewart Jackson.

Solid Geometry and Conic Sections, with Appendices on Transversals, and Harmonic Division, for the Use of Schools. By J. M. Wilson Second Edition. (Macmillan and Co., 1873.) ...