简介:提出求解一阶Lagrange力学逆问题的新途径;给出由一阶微分方程直接构造Lagrange函数的基本解法,以及几种与不同的补充条件相对应的特殊解法.举例说明所得结果的应用.
简介:近年来,若干文章对“Lagrange微分中值定理的逆问题”进行了讨论,但其表述均不完整,且证明也较繁琐。本文使用严格凸(严格凹)函数的性质,给出该问题一个条件较弱且表述较完整的结果,其证明也较简洁。
简介:总结了有限交换群和一般有限群情形下Lagrange定理的逆问题的探讨和结论,并分别给出了例子。特别地,对于有限非交换群情形下,Lagrange定理的逆问题一般有否定答案的情况给出例子——24阶置换群S4的所有偶置换的集形成的4次交代群不存在6阶子群来加以说明。
简介:ItisaclassicalresultofBernsteinthatthesequenceofLagrangeinterpolationpolynomialsto|x|atequallyspacednodesin[-1,1]divergeseverywhere,exceptatzeroandtheend-points.InthispaperweshowthatthesequenceofLagrangeinterpolationpolynomialscorrespondingtothefunctionswhichpossessbettersmoothnessonequidistantnodesin[-1,1]stilldivergeseverywhereintheintervalexceptatzeroandtheend-points.
简介:Thispaperconsiderstoreplace△m(x)=(1-x2)2(1/2)/n+1/n2inthefollowingresultforsimultaneousLagrangeinterpolatingapproximationwith(1-x2)2(1/2)/n:Letf∈C-1.10andr=[(q+2)/2],then|fk(x)-Pk(f,x)|=O(1)△na-k(x)ω(fa,△(x))(‖Ln-‖+‖Ln‖),0≤k≤q,wherePn(f,x)istheLagrangeinterpolatingpolynomialofdegreen+2r-1offonthenodesXnUYn(seethedefinitionofthetext),andthusgiveaproblemraisedin[XiZh]acompleteanswer.
简介:PropertiesofLebesguefunctionforLagrangeinterpolationonequidistantnodesareinvestigated.ItisprovedthatLebesguefunctioncanbeformulatedbothintermsofahypergeometricfunction2F1andJacobipolynomials.Moreover,anintegralexpressionofLebesguefunctionisalsoobtainedandtheasymptoticbehaviorofLebesgueconstantisstudied.
简介:Basedonthetheoryofcalculusofvariation,somesuffcientconditionsaregivenforsomeEuler-LagrangcequationstobeequivalentlyrepresentedbyfiniteoreveninfinitemanyHamiltoniancanonicalequations.Meanwhile,somefurtherapplicationsforequationssuchastheKdVequation,MKdVequation,thegenerallinearEulerLagrangeequationandthecylindricshellequationsaregiven.
简介:对Lagrange中值定理的证明,在高等数学的传统证法中,通常都是采用引入一个"辅助函数",将适合定理的函数转换成适合Rolle中值定理的函数的办法.为了进一步开阔思路,更好地理解和掌握Lagrange中值定理,本文给出了行列式证法、旋转变换证法和区间套定理证法等几种证明方法.
简介:Inthispaper,weproposeamortarelementmethodwithLagrangemultiplierforincompressibleStokesproblem,i.e.,thematchingconstraintsofvelocityonmortaredgesareexpressedintermsofLagrangemultipliers.WealsopresentP_1noncon-formingelementattachedtothesubdomains.Byprovinginf-supcondition,wederiveoptimalerrorestimatesforvelocityandpressure.Moreover,weobtainsatisfactoryapproximationfornormalderivativesofthevelocityacrosstheinterfaces.
简介:S.M.LozinskiiprovedtheexactconvergencerateatthezeroofLagrangeinterpolationpolynomialsto|x|basedonequidistantnodesin[-1,1].In2000,M.RevergeneralizedS.M.Lozinskii'sresultto|x|α(0≤α≤1).Inthispaperwewillpresenttheexactrateofconvergenceatthepointzerofortheinterpolantsof|x|α(1<α<2)..
简介:ThispaperestablishesthefollowingpointwiseresultforsimultancousLagrangeimterpolatingapproxima-tion:then|fk(x)-Pnk(f,x)|=O(1)△nq-k(x)ωwherePn(f,x)istheLagrangeinterpolatingpotynomialofdeereeonthenodesXnUYn(seethedefinitionofthenext).