Conic Sections from the Plane Point of View

With an appropriately chosen o-xyz system and property of the cone, the author has obtained an equation of the curve of intersection of a right circular cone and an inclined plane in the form x2 + Ay2 + By2 + Cy + D = 0, where the coefficients involve the vertex angle of the cone and the angle of the cutting plane. This form is the same as that derived from the locus definition of conic sections.