二次曲线

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

Mathematics The ratio of the distance of any point on a conic section from a focus to its distance from the corresponding directrix.

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

In the study of the relation of the tangent and the tangent point of conics,this paper will introduce a solution to the problem in seeking the tangent and the tangent point of conics,with mapping the tangent into tangent point or mapping the tangent point into tangent using mapping correspondence.

为了研究二次曲线的切线与其切点的关系，借助对射对应将切点映射成切线或将切线映射为切点，解决求二次曲线的切线和切点的问

A new algorithm of utter compensation, which is called " weighting method of compensation " for curve of the second order, has been developed.

提出了一种新的任意二次曲线半径补偿算法—加权补偿法，本算法用加权平均及权值修正技术，在插补过程中逐步地补偿刀具半径带来的偏移误差，解决了数控系统中非圆二次曲线必须靠分段近似来加工的难题。

The main results are as follows:(1) Based on the basic ideas of Hough transform and random Hough transform, a new method for the detection of general quadric curves was proposed, which used the representation of a family of quadric curves passing through four random selected points.

取得的主要结果如下：（1）基于Hough变换和随机Hough变换的主要思想，利用过四点的二次曲线簇表示，提出了一种一般二次曲线的检测方法。

Based on definitions and propositions and examples,it is first proposed the method of undetermined coefficients for normal quadratic curve equations.

0引言由二次曲线的射影定义可知，平面上任五个不同的点，其中没有四点共线，则过此五点唯一确定一条二次曲线。

Using the relations between harmonic conjugation elements,we can determine the relations between polar point and polar line more widely.

度量几何中圆的切割线之间所确定的数量关系，推广到射影几何里一般二次曲线中，利用调和共轭元素之间的关系，更广泛地确定了极与极线的相互关系，着重介绍了二次曲线的度量性质与射影性质的内在联系。

The aim of this article is to classify the definite value of quadric curve, to sum it up, to arrange it, and to give evidences of it.

把二次曲线中的定值进行了系统分类、归纳整理，并给予证明，可供学习二次曲线的性质时参考。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。