Ellipse:

In mathematics, an ellipse is a curve around two focal points on a plane, so for each point on the curve, the sum of the distances to the two focal points is constant. Therefore, it is a generalization of a circle, and it is a special type of ellipse with two focuses at the same position. The shape of an ellipse is represented by its eccentricity. For an ellipse, it is any number from 0 to near but less than 1.

An ellipse is a closed cone section: a plane curve intersects a plane through a cone. There are many similarities between the other two forms of ellipse and cone section: parabola and hyperbola, which are both open and unbounded. The cross section of a cylinder is elliptical unless it is perpendicular to the axis of the cylinder.

An ellipse can also be defined as a set of points, so that the ratio of the distance between each point on the curve and a given point (called focus) to the distance between the same point on the curve (called directrix) is a constant. This ratio is called eccentricity of ellipse. Ellipses can also be defined in this way. An ellipse is a collection of points, and the sum of the distances from these points to two focal points is a fixed number.

Use:

Elliptical lens, planetary orbit, orbit of rotating body; Or drag things around in the air with a hand rope to draw an approximate elliptical curve; Hyperbolic lens and reflector; Parabola, etc. Conic curves have many optical and geometric properties.

The ellipse mirror takes the long axis of the ellipse as the axis, rotates the ellipse by 180 degrees to form a three-dimensional figure, and its inner surface is all made into a reflective surface, which is hollow. Light emitted from one focal point can be totally reflected to another focal point.

Elliptical lens (with elliptical cross section) has the function of converging light (also called convex lens). Presbyopic glasses, magnifying glasses and farsighted glasses are all such lenses (these optical properties can be proved by reducing to absurdity). Ellipse is a conic curve, that is, the tangent of the cone and the plane; The circumference of an ellipse is equal to the length of a specific sine curve in a period.

Meaning:

Ellipse is widely used in real life. Generally speaking, people use it as a theme shape to show works of art, express emotions and make the vision more interesting.

In addition, the ellipse has many other uses, such as daily processing of motors, material processing and precision equipment, for production and assembly; Medical engineering also has the application of ellipse, which can be used for tissue regeneration, such as cell culture; Ellipse is also very important in architectural design, often used as doors and windows, decorative jewelry and so on.