两类特殊二元一次方程组的解

二元一次方程组{(1)当a:、b:、a一x b.夕=cla:x bZ少=cZc:和a:、b:、(!忿;会;},。)c:分别成等差数列时,方程组的解是{(2)当a:、b:、劣=一1y二2c;和a:、bZ、。2分别成等比数列且公比分别为q:、q,时,方程组的解是{y=证明:(l)一q一qZq一 q:将方程组改写成a:‘ (a: d:)夕=a: Zd;aZ二 (a: dZ)夕=a: Zd:(I)(I)(a:b:一匕:d:斗。)(I)xa:一(I)xa:,得(a;d:一a,dZ)夕=2(a Zd:一a,dZ)(2) 夕=2代入(I)〔或(I)〕得x=一1.将方程组改写成.’.广“一1 、夕=2。X q lyx q:y=好=q量(I)(F)(g:一Q:车。)(l(一(F),得(g:一g;)少=g荃.’.y=q: qZ,代入(l)一…     

ON THE NONLINEARTIMOSHENKO-KIRCHHOFF BEAM EQUATION

6o.IntroductionThemainresultsofthispaperwerepresentedin[4l.Letusconsiderthetransversalvibrationsu(x,t)(o5x5L,t2o)ofahomogeneousbeam.Inthefollowing,thelettersp,E,G(resp.S,I,k)withdenotetheusualphysical(resp.geometrical)paJrametersofthebeam.Moreprecisely,p:=volumedensity,E:=Youngmodulusofelasticity,G:=shearmodulus,S:=areaofthecrosssection,I:=momentofinertiaofthecrosssection,R2:=IS-',kisapositivenumber51whichdependsupon'thegeometryofthecrosssection(see[62,2o]),e.g.forrectangularcrosssection…     

BIFURCATION SOLUTION BRANCHESAND THEIR NUMERICAL APPROXIMATIONS OF A SEMI-LINEAR ELLIPTIC PROBLEM WITH TWO PARAMETERS

1.IntroductionConsidertheequationdependingontheparametersA,pER,wheref'R-Rands:R-RaresmoothoddfunctionandLetS'u(x)-u(T--x),r={S,I}.Then(l.l)isr-equivalent.Theequality(l.Za)isjustanormalizationoffatx=0.WeintroduceaSobolevspaceX:=Ha(0,7),anddefineamappingT'gEL'(0,T)u'=TaEXimplicitly'Aweakformof(1.1)inXxRZisDuetof(0)~0,theproblem(1.3)(resp.(1))hasatrivialsolutioncurveIfwerestrictp=0,then(l.3)reducestoaproblemwithsingleparameteranditsbifurcationsonthetrivialsolutioncurveCOarewellknown,…     

MATRIX ANALYSIS TO ADDITIVE SCHWARZ METHODS

1.IntroductionWeconsiderthefollowingsecondorderellipticboundaryvalueproblem:Lu=f,infl,(1)u=o,onOfl,(2)whereLisaselfadjointpositiveoperatorandflCnd(15dS3)isapolyhedraldomain.Aweaksolutionhasthefollowingform:FinduEHf(fl)suchthat:LetVh:=M=Span{rki},where{ghi}couldbenodalbasisconsistingofpiece-wiselinearfunctionsorothersplinefunctions-Substitutingthefollowingsolutionuh=Zui4iintotheaboveweakformleadstoadiscreteequationAu=f,(3)whereA=(crij),oij=A(ofi,rkj).(4)Itiswellknownthatthec0efficientmat…     

NUMERICAL APPROXIMATIONS OF A SEMI-LINEAR ELLIPTIC PROBLEM

1IntroductionConsidertl1eparameterdependentequationwhereA,ltERarepara1ueterandf:R-RandS:R-RaresinoothoddfunctionwithLetS1:u(x)-u(T-x),r={S1,I}then(l.1)isr-equivariant.Tl1eequality(1.2a)isjustanormalizatiolloffatx=o.Otherwise,onelllayreseektl1eparameterxtoensure(1.2a).To8implifyanalysisweintroduceaSobolevspaceX:=Hl(o,1)anddefilleamappingT:gEL'(o,T)-lL:=TgEXimp1icitly:for(Tg)'V'dx=-jorgl)dx,VvEX,aweakformof(1.1)inXxR2isDuetof(o)=O,theproblem(1.3)(resp.(1))hasatrivialsolutioncurvesC…     

BIFURCATION SOLUTION BRANCHES AND ITS NUMERICAL ANALYSIS OF A SEMI-LINEAR ELLIPTIC PROBLEM

1　IntroductionConsider the parameter dependent equationu"+ (λ+ s(μ) ) f( u) -μsinx =0　 in ( 0 ,π)u( 0 ) =u(π) =0 ( 1 .1 )whereλ,μ∈R are parameters and f:R→R and S:R→R are smooth odd functions anda) f′( 0 ) =1 ,　　 b) f ( 0 )≠ 0 ,　　 c) s( 0 ) =0 ,　　 d) s′( 0 ) =1 . ( 1 .2 )Let S:u( x)→ u(π-x) ,Γ ={ S,I} ,then ( 1 .1 ) isΓ -equivariant.The equality ( 1 .2 a) isjust a normalization of f at x=0 .Otherwise,one may reseek the parameter x to ensure( 1 .2 a) .To simplify an…     

WEAK SOLUTIONS TO THE TWO-DIMENSIONAL DERIVATIVE GINZBURG-LANDAU EQUATION

1.IntroductionInthepreselltpaper)westudythefollowinggeneralizedcomplexGinzburg-Landauequationintwospatialdimensions:anm=pp (1 in)au~(1 lp)Ill'"~ ox,.v(lul'u) p(x,.ac)lul',(1.1)whereallparametersarereal.Thisequation3mostlyconsideredwithor=P=0anda=1,hasalongandbroadhistoryinphysicsasagenericamplitudeequationneartheonsetofinstabilitiesinfluidmechanicalsystems,aswellasinthetheoryofphasetransitionsandsuperconductivity.Inthstspecialcase,theekistenceofsolutionsandtheirlongtimebehaviourhavebeeninves…     

直线与椭圆位置关系的一个判定定理的简证

文[1]证得下面: 定理若直线ι:Ax By C=0,(A2十B2≠0)与椭圆c:(x-x0)2/a2 (y-y0)2=1有公共点,则有:(Aa)2 (Bb)2≥(Ax0 By0 C)0. 本文给出上述定理的一个简单证明. 证明设x-x0/a=X,y-y0/y=Y,即x=x0 aX,y=y0 bY.则直线ι与椭圆c有公共点(?)方程组     

BOUNDARY ELEMENT APPROXIMATION OF STEKLOV EIGENVALUE PROBLEM FOR HELMHOLTZ EQUATION

1.IntroductionWeconsiderthefollowingStekloveigenvalueproblem:FindnonzerouandnumberA,suchthat--An u=0,infi,on,on=An,onr,(1.1)wherefiCRZisaboundeddomainwithsufficientsmoothboundaryr,4istheonoutwardllormalderivativeonr.CourantandHilb..tll]studiedthefollowingeigenvalueproblem:onac=0,infi,--~An,onr,(1.2)OnwhichwasreducedtotheeigenvalueproblemofanintegralequationbyusingtheGreen'sfunctionofAn=0withNuemannboundarycondition.FromFredholmtheorem,weknowthat(1)theproblem(1.2)hasinfinitenumberofeigenv…     

一个不等式的推广

本刊文[1]给出如下姊妹不等式:若a,b,c是正数,且a b c=1,则有1b c-ac 1a-ba 1b-c≥673(1)当且仅当a=b=c=31时取等号.1b c ac 1a ba1 b c≥1613(2)当且仅当a=b=c=31时取等号.不等式(1)可改写为:11-a-a1-1b-b1-1c-c≥673(3)当且仅当a=b=c=31时取等号.本文将把不等式(3)推广为:命题设xi>0(i=1,2,…,n),∑ni=1xi=1,则∏ni=1(1-1xi-xi)≥(n-n1-1n)n(4)当且仅当x1=x2=…=xn=1n时等号成立.引理设f″(x)>0,则1n∑ni=1f(xi)≥f(1ni∑=n1xi)(5)此即著名的Jesen不等式.下面给出(4)式的证明.证设y=f(x)=ln(1-1x-x)(0相似文献