Conic curves include ellipses, hyperbolas and parabolas.
1. ellipse: A trajectory whose sum of the distances from a moving point to two fixed points is equal to a fixed length (the fixed length is longer than the distance between the two fixed points) is called an ellipse. Namely: {p || pf 1 | | pf2 | = 2a, (2a >: |f 1f2|)}.
2. Hyperbola: The trajectory of a moving point with a fixed absolute value (the fixed value is less than the distance between two fixed points) is called hyperbola. That is {p |||| pf1| | pf2 || = 2a, (2a
3. Parabola: A trajectory with the same distance from a moving point to a fixed point and a fixed straight line is called parabola.
4. Unified definition of conic section: The locus of a point whose distance ratio e from a fixed point to a fixed line is constant is called conic section. When 0
Definition of solid geometry: The geometry formed by taking the straight line where the right side of a right triangle is located as the rotation axis and the other two sides rotating 360 degrees is called a cone. The axis of rotation is called the axis of a cone. The surface formed by rotating a surface perpendicular to the axis is called the bottom surface of the cone.