简介:一、单项选择题(每小题5分,共50分)1.已知点(3,-4),那么它到x轴的距离为( )(A)3 (B)4 (C)-3 (D)52.如果k>b>0,那么直线y=kx+b的图象必不经过( )(A)第一象限 (B)第二象限(C)第三象限 (D)第四象限3.函数y=kx的图象经过点(-2,2),那么直线y=kx-k的图象经过( )(A)第二、三、四象限 (B)第一、二、三象限(C)第一、二、四象限 (D)第一、三、四象限4.满足b<0,c<0的二次函数y=x2+bx+c的图象大致是( ) 5.两圆圆心都在y轴上,且两圆相交于A、B两点,若A点坐标为(2,2),则B点坐标为( )(A)(2,-2)
简介:Ю.И.Волков在[1]中构造了一系列一元及多元线性算子,其中包括二元Baskakov算子,本文讨论该算子在C空间的逼近性质。
简介:LetCdenotethesetofallk-subestsofann-set.AssumeAlohtaininCa,andAlohtainin(A,B)iscalledacross-2-intersectingfamilyif|AB≥2forandA∈A,B∈B.Inthispaper,thebestupperboundsofthecardinalitiesfornon-emptycross-2-intersectingfamillesofa-andb-subsetsareobtainedforsomeaandb,AnewproofforaFrankl-Tokushigetheorem[6]isalsogiven.
简介:Animprovedrandomizedalgorithmoftheequivalent2-catalogsegmentationproblemispresented.Theresultobtainedinthispapermakessomeprogresstoanswertheopenproblembyanalyzethisalgorithmwithperformanceguarantee.A0.6378-approximationfortheequivalent2-catalogsegmentationproblemisobtained.
简介:Assumethatm≥2,pisaprimenumber,(m,p(p-1))=1,-1(Z/mZ)~*and[(Z/mZ)~*:]=4.Inthispaper,wecalculatethevalueofGausssumG(X)=Σ_(x∈F_q~*)x(x)ζ_p~(T(x))overF_q,whereq=p~f,f=((m))/4xisamultiplicativecharacterofF_qandTisthetracemapfromF_qtoF_p.Underourassumptions,G(x)belongstothedecompositionfieldKofpinQ(ζm)andKisanimaginaryquarticabeliannumberfield.WhentheGaloisgroupGal(K/Q)iscyclic,wehavestudiedthiscycliceaseinanotherpaper:'Gausssumsofindexfour:(1)cycliccase'(acceptedbyActaMathematicaSinica,2003).Inthispaperwedealwiththenon-cycliccase.