平行四边形中一个面积比的性质及其空间拓广

文献[1]用共边定理探讨了三角形五心的一个相似性质，文献[2]用共边定理探讨了三角形的一个共点性质，并用共面定理将其进行拓广．笔者用共边定理对平行四边形进行探究得出了一个面积比的．陡质，并用共面定理将其进行空间拓广．     

局部L-凸空间中的ky Fan型截口定理及其应用

本文利用局部L-凸空间中的一个不动点定理,在局部L-凸空间中建立了一个新的截口定理,并利用该定理得到不动点存在定理。     

关于Lebesgue积分中的极限定理

本文首先给出了控制收敛定理的一个完全独立和更为直接的证明,同时提供了积分与极限可交换次序的一个充要条件,然后利用控制收敛定理来证明Levi渐升列定理,最后还讨论了Levi定理、Fatou引理和Lebesgue控制收敛定理之间的等价关系。     

关于有界收敛定理的一个注记

有界收敛定理是实变函数论中的一个重要定理,在很多实变函数论教材中,它常作为Lebesgue控制收敛定理的推论出现.我们利用叶果洛夫定理给出有界收敛定理的一个新的证明,并对有界收敛定理的条件进行了讨论.     

上同调元素对特征标扩张定理的影响

利用上同调元素的若干乘法性质获得了Gallagher经典特征标扩张定理的一个简化证明,从而避免了该定理对Brauer广义特征标刻划定理的依赖,另外,还得到了Gallagher经典特征标扩张定理的一个推广形式。     

控制收敛定理的一个处理方法

首先证明一个引理,然后利用该引理及几乎处处收敛型控制收敛定理证明依测度收敛型控制收敛定理。这样结合利用Fatou引理可较简捷证明几乎处处收敛型控制收敛定理的特点,从而为课堂上处理控制收敛定理提供了较理想的处理方法。并借助一个猜想给出了一个由依测度收敛型控制收敛定理直接证明几乎处处收敛型控制收敛定理的方法。     

达布定理与罗尔定理的等价性

给出了微分学中达布定理与罗尔定理等价性的证明,并且获得了不用费马定理而用实数的连续性定理和导数定义证明这两个定理的一个方法。     

微分中值定理教学刍议

微分中值定理是微积分学中一个重中之重的内容。学好了微分中值定理无疑便掌握了整个微积分学的一个关键所在。因而,如何教好微分中值定理就显得很重要了。     

高等代数中替换定理的一种证明

在向量的有关证明中,替换定理是高等代数中比较重要的一个定理,利用线性方程组和矩阵的相关理论给出了此定理的一个证明。     

微分中值定理逆命题的讨论

对于常见的三个微分中值定理(罗尔中值定理，拉格朗日中值定理，柯西中值定理)的逆命题何时成立的问题进行了讨论。对于f(x)仅有一个零点的情况得到了使罗尔中值定理逆命题成立的充要务件；对于一般情况，也得到了一个有价值的充要条件，利用辅助函数推广了关于罗尔中值定理逆命题的有关结果，得到了拉格朗日中值定理与柯西中值定理逆命题成立的条件。     

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?     

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.     

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.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

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.