查询词典 conic section

Abstract］ Objective To describe the shape of the planar space of the corneal anterior surface of children with emmetropia by using a conic section, and then to plot the changes in asphericity on 36 meridians to deduce the formulae of the three-dimensional shape of the corneal anterior surface.

目的 通过二次曲线方程来描述正视儿童角膜前表面的二维空间形态，根据各子午线非球面性的变化规律推导出其三维形态的数学表达式及非球面性变化规律表达式。

We will take the conic section teaching for an example as followed.

文章以圆锥曲线教学为例进行探讨和分析。

However, when determining the different orders of four points, there is difference existing in the conic section type.

但是，不同顺序的四点在决定二次曲线类型存在着差异。

B A new method for describing the projection of a line in an omni-image as a conic section is proposed.

b我们提出了一个利用圆锥曲线来描述环场影像中的直线投影的新方法。

We reseach the equation of conic section and obtain the equation which can give all plane conic section .

探讨二次曲线的方程，构造了一个可以表示平面上所有九种二次曲线的方程。

According to the fUndamental theorem of coniC In projective geometry any five points can decide one conic section .

在射影几何中，二次曲线定理告诉我们任意五点可以决定一条二次曲线。

Accoring to the polar theory of conic section, the characteristics of geometrical graphics concerning the conic section is discussed from following three aspects:the conbination of Point and line, harmony of point range and pencil of line , trace of point and enveloping of straight line.

本文根据二次曲线的配极理论，从点、线的结合性，点列和线束的调和性，点的轨迹和直线的包络三方面研究与二次曲线有关的几何图形的性质。

The ratio of the distance of any point on a conic section from a focus to its distance from the corresponding directrix. This ratio is constant for any particular conic section.

离心率二次曲线上任何一点到焦点的距离与到准线的距离之比对任一特定二次曲线来说，这个比值都是一个常数

Chapter Five shows the case study of the beauty of math in high school teaching. Conic section is taken as an example to unearth the beauty of mathematics in from the following three aspects: 1. the language beauty of conic section reveals the external formal beauty; 2. the methodological beauty and the logical beauty of conic section reflect the internal rational beauty; 3. the beauty of mathematics in conic section reveals the new value in internal knowledge structure of textbooks. Moreover, the application of the beauty of mathematics in high school math teaching is also discussed from the following four points of view: the pursuit of conciseness, the construction of symmetry, the utilization of unity and the discovery of uniqueness.

首先，以圆锥曲线教学为案例来挖掘中学数学教学中的数学美，具体从三个层次探讨①圆锥曲线语言之美，是数学美的外在形式美具体展现；②圆锥曲线方法美、逻辑美，是深层次数学美的内在理性美的反映；③在圆锥曲线的教学过程中，利用其数学美处理教材，揭示内在知识结构的新价值；其次，提出数学美在中学数学学习中的具体案例运用，并具体从追求简洁性、构造对称性、利用统一性和发现奇异性四个方面来举例探讨。

This article takes the teaching of conic sections as an example. By designing worksheets, teachers can introduce the historical material about conic sections to students. By way of using Apollonius' definition of parabola, ellipse and hyperbola, teachers can introduce the geometric aspect of "conic section" to students. By using the concept of " latus rectum " in Conics , we can connect "conic sections"-- representation of geometrical aspect, with "the equation of conic sections"-- representation of algebraic aspect to improving insufficiency of text books.

同时本文也试著从历史文本中寻找材料，简单举例说明数学教师可以如何应用这些史料在几何单元教学上，例如三角函数的正余弦定理，最后再以圆锥曲线的正焦弦为例，说明如何利用数学史料於此单元的教学，尤其是阿波罗尼斯的《锥线论》中对圆锥曲线的3个命题，将此3个命题的内容与意涵，尤其是正焦弦在圆锥曲线的几何意义上所扮演的角色，将其适当地融入教学中，将可使学生真正学习圆锥曲线的几何知识，而不再只是代数形式的几何知识。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。