谈积分运算中新发现的一条分部积分定理及其应用

针对高等数学微积分学中的不定积分运算里,经常遇到的被积函数是多项式与指数函数的乘积的情形,充分利用不定积分的分部积分法证明得出正文中提出的一条实用定理,切实方便读者遇到此类型积分时直接应用该定理运算出最后结果,结合使用牛顿-莱布尼兹公式,该定理应用将更加广泛、实用.     

线面垂直判定定理的向量证明

直线与平面垂直的判定定理的证明,是现行高中数学教材中的一个难点,其证明的过程,实质上就是由平面的轴对称转换为空间的镜面对称的过程,这种方法学生很难想到.用向量法证明线面垂直的判定定理,可以把几何综合推理与向量代数运算有机地结合起来,为学生的思维活动开发了更加广阔的天地,使学生对用向量知识解决垂直问题有了更加深刻的认识,这也是我国现行高中数学教材改编的重要之处.下面利用向量法证明线面垂直的判定定理:     

指向“数学运算”素养提升的初中方程教学寻绎——以“一元二次方程根与系数的关系”为例

“数学运算”是数学学科关键能力之一,它是数学学习过程中最基本的能力与素养,也是获取其他知识、技能、素养的基本工具.笔者有感于浙教版八年级下“一元二次方程根与系数的关系”这一课题的教学,既是学生对方程学习的深入探索与挖掘,也是对数学运算素养的内化与提升.从“亲历过程,在体验‘数学运算’中获得运算的方法与路径”“立足本质,在强化‘数学运算’中感悟运算的结构与变形”“拓展延伸,在深化‘数学运算’中提升运算的能力与素养”三个方面谈一谈“数学运算”能力提升的策略.     

利用Abel方法求级数的和

通过Abel引理给出了Abel定理的证明，并由此推出了级数乘法定理，利用它们可使级数的求和运算更为简便．     

相交弦定理在解析几何中的运用

解析几何的基本思想是用代数方法研究几何问题,偏重于相关量的数量关系研究.由于代数运算复杂,对运算能力要求较高,往往使很多学生对解析几何题望而生畏.事实上,解析几何问题的本质仍是几何问题,因此在解答解析几何问题时,若能充分把握解析几何中图形的特征,挖掘图形相应的几何性质,往往能简化运算,优化解题过程,从而事半功倍、别样精彩.     

空间向量的运算

正空间向量的数乘运算是空间向量的一种重要运算,掌握数乘运算的定义和运算律,特别是共线向量、共面向量的意义,理解共线向量和共面向量的定理及推论,并能用它们来证明空间向量的共线和共面问题.1空间向量的数乘运算例1如图1,在长方体ABCD-     

代数运算在几何证明中的运用

有些几何题，用代数法来证明往往会产生意想不到的效果，下面举例介绍用分式运算方法证明某此几何问题。     

重要极限在数列极限运算中的应用

数列的极限是指当项数n无限增大时数列的变化趋势。求极限是数学中一种重要的运算。极限运算与代数运算不同，代数运算是有限运算，而极限运算是无限运算。极限运算是事物运动变化由量变到质变这个辩证规律在数学中的反映。     

浅谈抽象函数的周期性问题

探讨了周期函数的判定定理和周期函数的运算性质.     

圆锥曲线直角弦上点轨迹的简捷求法与推广

文[1]与文[2]分别给出了圆锥曲线直角弦上点轨迹的统一方法，其中文[1]利用高等数学中的导数知识证明定理1，文[2]虽用初等数学方法证明了定理1，但证明过程过于繁琐，以中学生的运算能力难以完成．本文另辟蹊径，给出一种简捷证明方法，并对文[1]与文[2]中的结论进行推广，现介绍如下．     

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?     

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…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.