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1.
某些新解析不等式和不等式常数改进的实际用处   总被引:1,自引:0,他引:1  
曹家鼎 《应用数学》1992,5(4):106-108
本文建立一般不等式,推广了Hardy-Littlewood、Polya和Mitrinovic-Adamovic不等式,文中给出在抛射体(导弹)和火箭上的二个实际用处.Bellman说:“存在研究不等式的三个理由;实际的理论的和美学的.”我们构造抛射体(导弹)在真空中的弹着点(或水平射程)不等式.改进这不等式常数对战争的胜利有所帮助.在书[2][3]中证明了:  相似文献   

2.
文献[1]中得出了下述二次型三角形不等式:对锐角△ABC与任意实数x,y,z,有s-aax2+s-bby2+s-ccz2≥2(yzcosBcosC+zxcosCcosA+xycosAcosB)①其中a,b,c与s分别为三角形的三边与半周.最近,我们在...  相似文献   

3.
反向基本不等式及应用   总被引:1,自引:1,他引:0  
杨镇杭 《大学数学》2007,23(5):147-151
运用导数方法,对两个正数的基本不等式中的权数作了分析研究,给出了基本不等式的三个反向不等式;运用反向不等式,通过选取适当的权数,给出了指数平均的反向不等式,同时给出了涉及A,G,L,E的几个新的不等式.  相似文献   

4.
刘康宁 《数学通讯》2004,(9M):41-44
文[1]介绍了证明不等式的四种基本方法,下面将介绍证明不等式的三种常用技巧.  相似文献   

5.
胡桂荣 《数学通讯》2000,(18):18-20
不等式是中学数学的重要内容之一 ,而平均不等式是不等式中的重要不等式 ,这“重中之重”决定了它是永不衰退的高考热点 .事实也正是如此 ,近三年高考题中 ,1997年全国文、理第 2 2题 ,1998年全国文、理第 2 2题 ,1999年全国文、理第 2 0题都涉及到平均不等式 .因此正确理解、灵活运用平均不等式 ,掌握平均不等式求最值的技巧 ,将会使复杂的问题变得简单 ,收到事半功倍的效果 .1 正确理解平均不等式高中《代数》(必修 )下册P15第 11,12题所示两不等式稍作变形并结合起来是a2 b22 ≥ a b2 ≥ ab≥ 21a 1b(a ,b∈R ) .其推广…  相似文献   

6.
在北师大版新课标选修课本4-5,第26页,有一道不等式的证明题,结合所学三个重要不等式:均值不等式,排序不等式和柯西不等式,给出三个证明.  相似文献   

7.
本文解释一个不等式的几何意义,介绍不等式的三种证明方法.  相似文献   

8.
唐新来 《数学通讯》2003,(15):29-31
我们知道 ,任何三角形都有一个内切圆 ,切点把三边分成两段 .根据切线长定理 ,可将三边分拆换元 ,即在△ABC中 ,a ,b ,c分别为其三边长 ,可设a =y +z ,b =x +z ,c =x + y (其中 ,x ,y ,z∈R+ )( 1)如此便可简捷地证明一些三角形不等式 .下面我们举例说明 :1 分拆换元后 ,运用算术—几何平均值不等式一些结构较复杂 ,直接运用均值不等式有困难的三角形几何不等式 ,依据 ( 1)式分拆换元后 ,却能容易利用算术—几何平均值不等式 .例 1 在△ABC中 ,a ,b,c分别为其边长 ,求证 :① (《数学通讯》 2 0 0 1.12 .数学问题 132 4 )a +bb +c -a+ b…  相似文献   

9.
本文给出了有关矩的一些不等式在证明不等式中的应用。方法独特,简捷。  相似文献   

10.
待定系数法在基本不等式中的应用   总被引:1,自引:0,他引:1  
邬坚耀 《数学通讯》2002,(17):18-18
请先看一个例子 :例 1 有一块长为 2米宽为 1米的矩形铁皮 ,现要在四角各截去一个同样大小的正方形 ,然后做成无盖盒子 ,问该如何截方能使其容积最大 ?解 设截去的正方形边长为x米 ,则所做的盒子的容积为V =x(2 - 2x) (1- 2x) .此时 4V =4x(2 - 2x) (1- 2x)可以看成三个因式的乘积 ,而这三个因式的和为定值 .然而由于方程4x =2 - 2x =1- 2x无解 ,因此这时我们不能直接应用基本不等式3 x1x2 x3≤ x1+x2 +x33,x1,x2 ,x3∈R+来求解 .为了能用基本不等式求解 ,我们引入参数a ,b(0 <a <12 ,0 <b <12 ) ,此时x ,2a …  相似文献   

11.
A system of linear inequalities subject to nonnegativity restrictions is considered. General criteria which are necessary and sufficient for a linear inequality to be redundant are derived. This general characterization provides a basis for unifying some of the existing techniques. After taking into consideration the existence of redundant linear inequalities, general necessary and sufficient criteria for a linear inequality to be nonredundant are also obtained. An example is given to illustrate the application of these new criteria.The author wishes to thank the referee for his comments.  相似文献   

12.
We extend the Novikov Morse-type inequalities for closed 1-forms in 2 directions. First, we consider manifolds with boundary. Second, we allow a very degenerate structure of the critical set of the form, assuming only that the form is non-degenerated in the sense of Kirwan. In particular, we obtain a generalization of a result of Floer about the usual Morse inequalities on a manifold with boundary. We also obtain an equivariant version of our inequalities.

Our proof is based on an application of the Witten deformation technique. The main novelty here is that we consider the neighborhood of the critical set as a manifold with a cylindrical end. This leads to a considerable simplification of the local analysis. In particular, we obtain a new analytic proof of the Morse-Bott inequalities on a closed manifold.

  相似文献   


13.
Best constants in the Hardy-Rellich inequalities and related improvements   总被引:1,自引:0,他引:1  
We consider Hardy-Rellich inequalities and discuss their possible improvement. The procedure is based on decomposition into spherical harmonics, where in addition various new inequalities are obtained (e.g. Rellich-Sobolev inequalities). We discuss also the optimality of these inequalities in the sense that we establish (in most cases) that the constants appearing there are the best ones. Next, we investigate the polyharmonic operator (Rellich and higher order Rellich inequalities); the difficulties arising in this case come from the fact that (generally) minimizing sequences are no longer expected to consist of radial functions. Finally, the successively use of the Rellich inequalities lead to various new higher order Rellich inequalities.  相似文献   

14.
15.
We consider monotone ∨,∧-formulae φ of m atoms, each of which is a monotone inequality of the form fi(x)?ti over the integers, where for i=1,…,m, fi:Zn?R is a given monotone function and ti is a given threshold. We show that if the ∨-degree of φ is bounded by a constant, then for linear, transversal and polymatroid monotone inequalities all minimal integer vectors satisfying φ can be generated in incremental quasi-polynomial time. In contrast, the enumeration problem for the disjunction of m inequalities is NP-hard when m is part of the input. We also discuss some applications of the above results in disjunctive programming, data mining, matroid and reliability theory.  相似文献   

16.
Cases of equality in certain Hardy–Riesz–Rogers–Brascamp–Lieb–Luttinger rearrangement inequalities are characterized.  相似文献   

17.
The sharp Sobolev inequality and the Banchoff-Pohl inequality on surfaces   总被引:1,自引:0,他引:1  
Let be a complete two dimensional simply connected Riemannian manifold with Gaussian curvature . If is a compactly supported function of bounded variation on , then satisfies the Sobolev inequality

Conversely, letting be the characteristic function of a domain recovers the sharp form of the isoperimetric inequality for simply connected surfaces with . Therefore this is the Sobolev inequality ``equivalent' to the isoperimetric inequality for this class of surfaces. This is a special case of a result that gives the equivalence of more general isoperimetric inequalities and Sobolev inequalities on surfaces.

Under the same assumptions on , if is a closed curve and is the winding number of about , then the Sobolev inequality implies

which is an extension of the Banchoff-Pohl inequality to simply connected surfaces with curvature .

  相似文献   


18.
19.
Several existence results for a class of perturbed inequality problems on various subsets of Banach spaces are proved. A concrete application to a problem from Nonsmooth Mechanics illustrates is given. This paper is dedicated to the memory of Professor P.D. Panagiotopoulos  相似文献   

20.
We give a direct proof of the ‘upper’ Khintchine inequality for a noncommutative symmetric (quasi-)Banach function space with nontrivial upper Boyd index. This settles an open question of C. Le Merdy and the fourth named author (Le Merdy and Sukochev, 2008 [24]). We apply this result to derive a version of Rosenthal?s theorem for sums of independent random variables in a noncommutative symmetric space. As a result we obtain a new proof of Rosenthal?s theorem for (Haagerup) Lp-spaces.  相似文献   

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