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Liénard方程极限环的存在唯一性定理 总被引:1,自引:0,他引:1
<正> 的极限环的存在唯一性问题[1,2],给出了定理1,此定理的一个推论即已包含了熟知的Lienard定理以及Levinson-Smith[3],Sansone[2],Barbalat[4],余澍祥[5]的存在唯一性定理.作为定理1推论的直接应用,还对方程 相似文献
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本文在不假定 G 在紧集 X 上满足 Haar 条件的情形,建立了 Dunham 型联合最佳逼近的 Chebyshev 理论,包括特征定理(定理5、定理6和推论2),唯一性与强唯一性定理(定理9和推论3)以及连续性定理,同时我们也得到了“削皮”定理与联合最佳逼近的量的对偶形式。(定理7)。 相似文献
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一般中学教科书正弦定理与余弦定理都是分别加以证明的。这两个定理之间互有联系。如已证明正弦定理,余弦定理可成为正弦定理的推论。反之,如余弦定理先成立,正弦定理亦可成为余弦定理的推论。因此两者不是独立的。 相似文献
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和圆有关的比例线段中,有相交弦定理与推论、切割线定理与推论等.如果你注意观察就可发现,所有的定理与推论,都是相交弦定理这个演员扮演的.不信就请听我说. 如图1,圆O中,弦AB、CD相交于P,则PA·PB=Pc·PD.这就是相交弦定理. 相似文献
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Cramer定理之推论的扩充及其对其它定理新证明的应用成如翼(北京航空航天大学)由于求解线性方程组的Cramer定理的推论中,只给出了齐次线性方程组只有零解的充分条件和有非零解的必要条件,因此这对某些基本定理的证明带来很多不便,致使某些论证和推理都要... 相似文献
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极限论是微积分中基础和重要的概念.数列极限的迫敛性定理既能判断数列的收敛性,也给出其极限值。通过对数列极限迫敛性定理的条件加以改进,得到了它的推论,并用一个例子说明了该推论的应用。 相似文献
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教学目的:使学生了解和圆有关的角的定义,掌握相应的度数定理及推论,并能熟练运用。重点:圆周角定理及证明。难点:分三种情况证明定理。课时安排:两课时,第一课时到推论二。教学过程: 相似文献
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微分中值定理的结论是在开区间内至少存在一点使得某个等式成立,不妨把这样的点称为微分点;积分中值定理的结论也是在开区间内至少存在一点使得某个等式成立,不妨把这样的点称为积分点.本文讨论这两类点之间是否有关系,以及关系如何的问题,指出相关文献所提供的若干个结论中,有不只一个存在错误. 相似文献
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《Journal of Mathematical Analysis and Applications》1987,122(2):393-407
We provide some new Caratheodory-type selection theorems, i.e., selections for correspondences of two variables which are continuous with respect to one variable and measurable with respect to the other. These results generalize simultaneously Michael's [21]continuous selection theorem for lower-semicontinuous correspondences as well as a Caratheodory-type selection theorem of Fryszkowski [10]. Random fixed point theorems (which generalize ordinary fixed point theorems, e.g., Browder's [6]) follow as easy corollaries of our results. 相似文献
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在本文中,我们研究了一类集值严格集-压缩映象的一致极限映象.建立了这类一致极限映象的不动点指数理论,证明了某些正不动点定理.我们的定理推广了Fitzpatrick和Petryshyn的某些最近结果. 相似文献
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第二型曲线积分的第二中值定理 总被引:1,自引:0,他引:1
唐国吉 《数学的实践与认识》2009,39(17)
引入了定义在曲线上的函数的单调性概念,在此基础上证明了第二型曲线积分的第二中值定理.定积分的第二中值定理是主要结果的简单推论. 相似文献
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In the present paper we use a control function to define a generalized contraction in Menger spaces and obtain a unique fixed point theorem. The work is in line with the research for developing probabilistic contractions with the help of control functions and related fixed point results. We have given an example to which our theorem is applicable. Some corollaries are also discussed. 相似文献
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In this paper the following results are got 1. We prove that the order definitionwhich is given by J.F. Trawb on the iterative function is wrong. 2. A existent theorem on the repulsive point is given. 3. We give some theorems to judge a fixed point of iterative function. They all imporve the Ostrowski's theorems. 相似文献
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In monographs [Theory of Limit Cycles, 1984] and [Qualitative Theory of Differential Equations, 1985], eleven propositions by several mathematicians are listed on the uniqueness of limit cycles for equations of type (I), (II), and (III) of the quadratic ordinary differential systems. In this paper, we first point out that all these propositions were not completely proved since the equations under consideration do not satisfy the conditions of the theorems used to guarantee the uniqueness of limit cycles. Then we give a new set of theorems that guarantee the uniqueness of limit cycles for the Liénard systems, which not only can be applied to complete the proof of the propositions mentioned above but generalize many other uniqueness theorems as well. The conditions in these uniqueness theorems, which are independent and were obtained by different methods, can be combined into one improved general theorem that is easy to apply. Thus many of the most frequently used theorems on the uniqueness of limit cycles are corollaries of the results in this paper. 相似文献