共查询到20条相似文献，搜索用时 109 毫秒
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詹国梁 《苏州教育学院学报》1984,(1)
利用定义证明数列极限或函数极限在极限理论教学中占有一定的地位,它既能加深学员对数列极限的“ε—N”定义、函数极限的“ε—N”或“ε—δ”定义的理解,又能提高学员逻辑推理的能力,为进一步学好数学分析奠定基础。 证明极限的实质在于求出仅与预先给定的任意小正数ε有关的N(ε)或δ(ε)。确切地说,对于数列极限就是需要找出满足不等式|x_n-a|<ε(其中x_n表示数列的通项)的充分条 相似文献
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王亮亮 《吕梁高等专科学校学报》2008,24(2)
以函数极限的ε-δ定义为基础,通过对同一个函数的三种不同极限的证明,帮助学生理解ε-δ定义的本质,进而提高学生灵活应用极限定义解决问题的能力. 相似文献
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卢翼飞 《中国科教创新导刊》2007,(6):54-55
用ε-δ语言证明函数的极限,关键在于对任意给定的正数ε,如何找出相应的正数δ,多项式函数极限的证明也是如此.本文采用配方的方法找出了这样的δ,从而使多项式函数的证明问题得到规范化、公式化的解决. 相似文献
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本文就用数列极限“ε-N”定义，函数极限“ε-δ”定义的证明过程中，为解不等式的需要，对N，δ进行适当限定的目的，技巧进行了讨论。 相似文献
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对刻画函数极限概念的ε-δ定义的几何意义提出了新的思考，并以实例加以阐明，认为用“蝴蝶结”形区域能更准确、全面地解释函数极限概念的ε-δ定义。 相似文献
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在用“ε—δ”语言证明有理函数极限lim x→α f(x)/g(x)=A的过程中,常要限定|x-α|<δ’来加强不等式|f(x)/g(x)-A|,于是δ’的选择便是关键,本文给出了一个选择δ’的方法,在实用中即方便又准确。 相似文献
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总体来说,中学生对数学概念中隐含的实无限认识不足,影响学生实无限认识的主要因素是整体认知.极限的ε-δ定义是学生普遍感到困难的知识点,只有理解了ε-δ定义中的实无限涵义才能真正理解极限的定义.学生能否抓住ε-δ定义中的"有分界"的无限,是理解ε-δ定义的关键.教学中应帮助学生挖掘概念背后的实无限思想,培养学生的无限观.帮助学生分析概念中隐藏的无限.在ε-δ定义的教学中,教师应从无限操作过程、无限思辨方式、ε、δ本身具有的任意性和存在性的双重内涵、集合论知识角度详细诠释"有分界"的无限涵义,使学生更容易理解证明中的"适当放大",从而深刻理解ε-δ定义的操作性内涵. 相似文献
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从三个方面阐述了如何抓住“ε-δ”定义的实质,来正确理解极限定义,并举例说明对任意给定的ε>0,如何去寻找正数δ的方法。 相似文献
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我们知道,极限知识在微积分的发展中扮演了一个非常有趣的角色:17世纪,牛顿和莱布尼茨发明微积分时,极限并未出现;18世纪,微积分进一步深入发展时,达朗贝尔尝试用极限观点对微积分的有关量进行表述(比如定义量Y的极限为X,如果"量Y可任意逼近X,这就是说,Y与X之间的差可任意小");19世纪分析严格化时,柯西和魏尔斯特拉斯建立了严格的极限理论(极限的ε-δ表述),从而完成了微积分在严格化基础上的重建.虽然极限的ε-δ表述为微积分提供了严 相似文献
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《海外英语》2007,(5):10-11
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? 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
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。 相似文献
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《海外英语》2007,(4):36
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. 相似文献
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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. 相似文献
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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. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献