蝴蝶定理的衍变推广

蝴蝶定理是欧氏几何中与圆有关的一个重要定理，而欧氏几何又是射影几何的子几何，本文将利用射影变换将圆映射为常态的二次曲线，从而将蝴蝶定理衍变推广为射影几何的命题，以丰富的射影几何的内容。     

蝴蝶定理的衍变推广

蝴蝶定理是欧氏几何中与圆有关的一个重要定理 ,而欧氏几何又是射影几何的子几何 ,本文将利用射影变换将圆映射为常态的二次曲线 ,从而将蝴蝶定理衍变推广为射影几何的命题 ,以丰富的射影几何的内容     

欧氏几何命题的射影证明及推广

本文介绍了射影几何理论在欧氏几何命题证明中的应用及推广,在射影几何观点下探讨一些欧氏几何命题的内在联系,从而加深对欧氏几何理论和方法的理解,获得在较高观点下处理欧氏几何问题的能力.     

一道经典几何命题的多种证明与推广

本文通过研究,给出一道经典几何命题--蝴蝶定理的六种证法.同时,利用射影变换知识,易将此命题进行系列衍变推广.     

高观点下的初等几何之共点问题

在克莱因变换群理论下,欧氏几何是射影几何的子几何.因此,可以说射影几何学的思想理论对欧氏几何具有一定的指导意义.本文仅从几个射影理论就初等几何中的直线共点问题的证明方法进行研究.     

几个初等几何命题的射影推广

本用射影理论推广初等几何中的六个与圆有关的命题。     

走出欧氏几何

本文论述了射影几何中理想元素、复元素和对偶元素的引入对几何学从欧氏几何发展到射影几何的重要作用，分析了由此导出的两种特殊的证明方法和作图方法。     

高等几何的高观点及其作用

对高等几何的高观点及其对中学几何的指导作用作了讨论,具体阐述了无穷远元素的应用,介绍了变换群观点,给出了推广新的欧氏几何命题的方法。以便更深入地理解几何空间的基本特征、研究方法、内在联系,从而提高处理中学几何问题的能力。     

射影观点下的蝴蝶定理

用射影几何观点研究糊蝶定理的推广命题及演变命题,并给出新的结果。     

几个初等几何命题的射影推广

本文用射影理论推广初等几何中的六个与圆有关的命题。     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.