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1.
在很久很久以前,有两个年轻人,一起去遥远的地方寻找幸福和快乐,一路上风餐露宿,历尽艰辛,在即将到达目的地时,遇到了一条风急浪高的大河.对于如何渡过这条河,两人有不同的意见:一个人建议砍伐附近的树造一条木船渡过河去,另一个人则认为这么高的浪,这么湍急的水流,这么宽的河面,无论造多大的船都不可能渡过这条河,与其自寻烦恼和死路,不如等这条河干了,再轻轻松松地走过去. 相似文献
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近年来,数学探索题以多彩优美的格调,清新多姿的风彩,发散开放的题型,背景育人的功能,注重能力的考查,强化创新的意识,出现在全国各地的中考试卷上,并有逐年上升之势,促进了生动、活泼、主动的数学学习活动,真正起到了实施素质教育“指挥棒”的作用,本文旨对近年来中考数学探索题作些归类,并对具体实例进行评析. 相似文献
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人教版教材第二册(上)第八章第二节讲的是椭圆的简单几何性质,在对称性中有这样的描述,在曲线的方程中,如果以-y代y方程不变,那么当P(x,y)在曲线上时,它关于x轴的对称点P′(x,-y)也在曲线上,所以曲线关于x轴对称,同理如果以-x代x方程不变,那么曲线关于y轴对称,如果同时以-x代x,以 相似文献
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每一道习题都有着严密的逻辑性,已知条件不可能多余,也不可能短缺,在所有条件中,抓住其最有特征性的一个,联想展开,这是解题的一种途径.许多同学在解题时,往往不去认真推敲题目中给出的已知条件,对于一些细小的似乎是不起眼的说明,便不去深入探讨,弃之一旁,熟视无睹,这是一个极大的错误.很多时候,若能紧紧抓住这些小条件,便可从这里打开缺口,解决大问题. 相似文献
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第一次世界大战结束后,美国经济进入繁荣时期。伴随着经济的繁荣,美国的股市也不断攀升,一直持续着牛市行情。然而,好景不长,1929年,全球金融危机爆发,华尔街股市大崩盘,让高盛损失了92%的原始投资,公司的声誉一落千丈,濒临倒闭,沦为华尔街的笑柄、错误的代名词。 相似文献
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著名数学家华罗庚说过:善于退,足够的退,退到最原始而不失去重要的地方,是学好数学的一个诀窍.这里所谓的退,当然不是逃跑,而是养精蓄锐,蓄势待发,是在为进寻求途径,即以退为进.它的实质是借助转化的数学思想,把复杂的问题简单化,运动的问题静止化,高维问题低维化,变量问题常量化,抽象问题具体化,代数问 相似文献
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一般化与特殊化是人类认识事物的两个重要侧面,也是解题的两种基本策略,它们相辅相成,是辩证的统一.在多数场合,特殊问题简单、直观,容易认识,容易把握.但是,也有一些场合,特殊问题的个别特性可能会掩盖事物的本质属性,给解题带来困难,而直接求解相应的一般性问题,反而来得简便、明快、奇巧. 相似文献
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近几年来,矩形纸片的折叠问题频繁出现在全国各地的中考数学试题中,此类问题贴近同学的认知规律,能较好考查基础知识和综合运用数学知识解决问题的能力,因此,很受命题者的青睐.但是,由于矩形折叠型试题涉及知识面广,结构独特,解法灵活多样,同时融合了丰富的数学思想和方法,所以大多数同学都感到有一 相似文献
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李冲 《高等学校计算数学学报(英文版)》1993,(1)
In this paper, we establish a new type of alternation theory for more general restricted ranges Chebyshev approximation with equalities. The uniqueness and strong uniqueness theorems are given. Applying the results, we obtain the alternation theorem and uniqueness theorem for best coposilive approximation. 相似文献
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《Nonlinear Analysis: Theory, Methods & Applications》2005,61(5):781-821
A convergence theorem and an approximation theorem for semigroups of Lipschitz operators are given. These theorems are applied to a semi-discrete approximation problem for a quasi-linear wave equation with damping and a finite difference method for a quasi-linear equation of Kirchhoff type. 相似文献
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《Applied Mathematics Letters》2007,20(7):806-812
In this work a new type of approximation operator—the Bézier variant of the BBHK operator—is introduced. Its approximation properties are studied. A convergence theorem for such approximation operators for locally bounded functions is established by means of some techniques of probability theory and analysis methods. This convergence theorem subsumes the approximation of functions of bounded variation as a special case. 相似文献
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A KY FAN MATCHING THEOREM FOR TRANSFER COMPACTLY OPEN COVERS AND THE APPLICATION TO THE FIXED POINT 总被引:6,自引:0,他引:6 下载免费PDF全文
文开庭 《数学物理学报(A辑)》2006,26(6):1159
In this article, a Ky Fan matching theorem for transfer compactly open covers is established. As applications, a Fan-Browder coincidence theorem, a Ky Fan best approximation theorem and a Brouwer-Schauder-Rothe type fixed point theorem are obtained. 相似文献
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文开庭 《数学物理学报(A辑)》2006,(Z1)
In this article, a Ky Fan matching theorem for transfer compactly open covers is established. As applications, a Fan-Browder coincidence theorem, a Ky Fan best approximation theorem and a Brouwer-Schauder-Rothe type fixed point theorem are obtained. 相似文献
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The Voronovskaya theorem which is one of the most important pointwise convergence results in the theory of approximation by linear positive operators (l.p.o) is considered in quantitative form. Most of the results presented in this paper mainly depend on the Taylor’s formula for the functions belonging to weighted spaces. We first obtain an estimate for the remainder of Taylor’s formula and by this estimate we give the Voronovskaya theorem in quantitative form for a class of sequences of l.p.o. The Grüss type approximation theorem and the Grüss-Voronovskaya-type theorem in quantitative form are obtained as well. We also give the Voronovskaya type results for the difference of l.p.o acting on weighted spaces. All results are also given for well-known operators, Szasz-Mirakyan and Baskakov operators as illustrative examples. Our results being Voronovskaya-type either describe the rate of pointwise convergence or present the error of approximation simultaneously. 相似文献
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In this paper, the concept of lacunary equi-statistical convergence is introduced and it is shown that lacunary equi-statistical
convergence lies between lacunary statistical pointwise and lacunary statistical uniform convergence. Inclusion relations
between equi-statistical and lacunary equi-statistical convergence are investigated and it is proved that, under some conditions,
lacunary equi-statistical convergence and equi-statistical convergence are equivalent to each other. A Korovkin type approximation
theorem via lacunary equi-statistical convergence is proved. Moreover it is shown that our Korovkin type approximation theorem
is a non-trivial extension of some well-known Korovkin type approximation theorems. Finally the rates of lacunary equi-statistical
convergence by the help of modulus of continuity of positive linear operators are studied.
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It is shown that a class of generalized mixed exponential type integral operatos on direct theorem of approximation and inverse theorem of approximation hold in CN(I). 相似文献
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Mehmet Ali Özarslan Hüseyin Aktuğlu 《Mathematical Methods in the Applied Sciences》2015,38(9):1937-1944
In this paper, we prove a certain Korovkin type approximation theorem by introducing new test functions. We introduce the non‐tensor Balázs type Bleimann, Butzer and Hahn operators and give the approximation property by using this new Korovkin theorem. Furthermore, we obtain the rate of convergence of these operators by means of modulus of continuity. Finally, we state the multivariate version of the abovementioned Korovkin type theorem. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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This paper is devoted to study direct and converse approximation theorems of the generalized Bernstein operators Cn( f,sn,x) via so-called unified modulus ω2φλ( f,t), 0 ≤λ≤1. We obtain main results as follows ω2φλ( f,t) =O(tα)|Cn( f,sn,x)- f(x)| =O(n-12 δ1-λn(x))α,where δ2n(x) =max{φ2(x),1/n} and 0 α 2. 相似文献