Brunn-Minkoeski有关面积的不等式的证明(英文)

给出Brunn-Minkoeski有关面积的不等式A01≥A0A1的一个特殊证明.首先给出一个二阶常微分方程满足初始条件的特解问题的描述形式,再将微分方程的特解问题转换成等价的变分问题,最后将相应几何量代入微分方程与变分问题相应公式中得到结论。     

关于二阶变系数线性微分方程的求解方法

若知道二阶变系数齐次线性微分方程的一个非零特解,则可以求出它的通解。同时也能推导出相应的二阶变系数非齐次线性微分方程的通解。并且本文也给出了一些求二阶变系数齐次线性微分方程非零特解的构造方法。     

二阶变系数线性微分方程的特解

在已知二阶变系数齐次微分方程的一个非零特解的条件下,可以得到该齐次微分方程和与它对应的非齐次微分方程的通解,本文给出了在二阶变系数齐次微分方程的系数满足一定条件下的特解形式.     

常微分方程中比较系数法的推广

将求常系数微分方程特解的比较系数法，推广至一些特殊的变系数微分方程，并给出了证明和计算公式.     

一类n维变系数非齐线性微分方程组特解的简捷求法

给出一类n维变系数非齐线性微分方程组特解的简捷求法 ,并提供了特解的表达式     

一类n维变系数非齐线性微分方程组特解的简捷求法

给出一类n维变系数非齐线性微分方程组特解的简捷求法，并提供了特解的表达式。     

二阶变系数线性微分方程的解

给出了二阶变系数线性微分方程的一些可解条件,及对应的齐次方程的一些特解形式。     

二阶变系数线性非齐次微分方程的通解

时于形如yn+a(x)y'+b(x)y=0的二阶变系数常微分方程,在已知一个特解y1(x)的情况下,通过线性变换,找到了一个既与y1(x)线性无关又可由变系数a(x)、b(x)共同表出的特解y2(x),从而使二阶变系数线性非齐次常微分方程的通解可用其变系数a(x)、b(x)明确地表达出来.     

常系数非齐次线性微分方程组的微分算子解法

给出了常系数非齐次线性微分方程组特解的一种新的公式化求解方法.它使求特解更加简易.     

一类常系数非齐次线性微分方程特解的迭代求法

给出一类常系数非齐次线性微分方程特解的迭代求法及相应的Fortran95程序,从算法上避免了拉格朗日系数变易法与待定系数法的繁杂运算,从实践上为利用计算机求解微分方程提供了理论保证与操作程序.     

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,     

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.     

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?     

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.