复数加减运算几何意义的证明

人教版高中代数下册P186,用平行四边形性质及三角形全等证明了复数加法的几何意义.在学习过程中,我们发现用中点坐标公式证明更为简便.下面给出证明: 设OZ1及OZ2分别与复数a bi及c di对应,且OZ1与OZ2不在同一直线上(如右图),以OZ1及OZ2为两条邻边画□OZ1ZZ2,则点Z1、Z2的坐标分别为Z1(a,b),Z2(c,d).由平行四边形性质,M是Z1Z2中点,所以点M的坐标为M(a b/2,b d/2),M是OZ的中点,所以点Z的     

ATIYAH INVARIANT, HIRZEBRUCH SUM AND PELLIAN EQUATION

The main result of this note is as follows: Let M=∈SL(2,Z) be hyperbolic. Then the Atiyah's invariant η(M)=-sign (trac (M))|m (M) Ψ_o (M), whore m(Mr) is the index of M in the stable subgroup for of the PSL (2, Z), and Ψ_o(M) =1/3Ψ(α).     

Multi-window Gabor frames and oblique Gabor duals on discrete periodic sets

Given L, N, M ∈ N and an NZ-periodic set S in Z, let l2(S) be the closed subspace of l2(Z) consisting of sequences vanishing outside S. For f = { fl : 0≤l≤L-1 }l2(Z), we denote by G(f, N, M) the Gabor system generated by f, and by L(f, N, M) the closed linear subspace generated by G(f, N, M). This paper addresses density results, frame conditions for a Gabor system G(g, N, M) in l2(S), and Gabor duals of the form G(a, N, M) in some L(h, N, M) for a frame G(g, N, M) in l2(S) (so-called oblique duals). We ob...     

Variational Principle for Topological Pressure on Subsets of Free Semigroup Actions

We investigate the relations between Pesin–Pitskel topological pressure on an arbitrary subset and measure-theoretic pressure of Borel probability measures for finitely generated semigroup actions. Let(X, G) be a system, where X is a compact metric space and G is a finite family of continuous maps on X. Given a continuous function f on X, we define Pesin–Pitskel topological pressure P_G(Z, f)for any subset Z ■ X and measure-theoretical pressure P_(μ,G)(X, f) for any μ∈ M(X), where M(X)denotes the set of all Borel probability measures on X. For any non-empty compact subset Z of X, we show that P_G(Z, f) = sup{P_(μ,G)(X, f) : μ∈ M(X), μ(Z) = 1}.     

Torsions of 3-Dimensional Small Covers

In this paper,it is shown that for a 3-dimensional small cover M over a polytope P,there are only 2-torsions in H1(M;Z).Moreover,the mod 2 Betti number growth of finite covers of M is studied.     

一道求椭圆标准方程题的流行错题

题目：已知椭圆M的两个焦点分别是F1（～1，0），F2（1，0），P是椭圆上的一点，且PF1⊥PF2，｜PF1｜-｜PF2｜-8，求椭圆的标准方程．     

错在哪里

题目设抛物线C：y^2=8x，若椭圆D的左焦点F和相应的左准线l分别与抛物线的焦点、准线重合，椭圆短轴的一个端点为B，且线段BF的中点M到定点A(m，0)的距离的最小值是√3，试求实数例的值及此时的椭圆方程．     

有趣的“蓝精灵画册”问题

肖文强先生在文[1]中提出一个很有趣的概率问题。香港商人为迎合儿童情趣推出一种“蓝精灵画册”,里面刊有180帧空白画框,附上文字要做成一本七彩悦目的故事书必须另外购买彩图贴成相应的框里.彩图放在小包里出售,每包6张,售价2元.每包外表是一个式样,买回来才知道里面的6张是什么.要估计需花多少钱才能买全那180张彩图? 一、顺序装包的情况 设彩图小包的包装是规定:1*一6*放一包,7#一 12#放一包, 13#一 18#放一包,以此类推.记买X(M)包可得M种不同的小包,则有递推公式(1):H(M+ 1)=X(M)+Z(M)其中Z (M)指要多买Z(M)包才得到一种与先前得…     

On the bilinear and cubic forms of some symplectic connected sums

Let ( M1 , M2 , N ) be three symplectic manifolds and suppose that we can do the symplectic connected sum of M1 and M2 along their submanifold N to obtain M1#NM2 . In this paper, we consider the bilinear and cubic forms of H* (M1#NM2 , Z) when dim M1#NM2 = 4, 6. Under some conditions, we get some relations of the bilinear and the cubic forms between M1#NM2 and M1■M2 .     

生成Q元M序列的理论和算法

本文定义了Q=Z/(q)上任意非奇异反馈移位寄存器的因子关联图。给出了一个构造Q上M序列的基本原理。进而给出了几个生成Q上M序列的无记忆算法。     

广义非中心Wishart分布

设Z是n×m随机矩阵(n>m),它具有椭球等高分布Z～LEC_n×m(M,Σ,φ),Σ>0,其密度函数为     

The Bergman kernel function of some Reinhardt domains (Ⅱ)

The boundary behavior of the Bergman kernel function of a kind of Reinhardt domain is studied. Upper and lower bounds for the Bergman kernel function are found at the diagonal points (Z,(Z-)). Let Ω be the Reinhardt domainm(X) where αj>0,j=1,2,…,n,N=N1+N2+…+Nn,‖Zj‖ is the standard Euclidean norm in CNj,j=1,2,…,n; and let K(Z,(W-)) be the Bergman kernel function of Ω. Then there exist two positive constants m and M,and a function F such that mF(Z,(Z-))≤K(Z,(Z-))≤MF(Z,(Z-))holds for every Z∈Ω. Here (X) and r(Z)=‖Z‖α-1 is the defining function of Ω. The constants m and M depend only on α=(α1,…,αn) and N1,N2,…,Nn,not on Z. This result extends some previous known results.     

2004年高考数学模拟训练试题

选择题　本大题共 12小题 ,每小题 5分 ,共 6 0分 .在每小题给出的四个选项中 ,只有一项符合题目要求 .1.设集合M ={x|x =4k± 1,k∈Z} ,N ={x|x =2k +1,k∈Z} ,其中Z表示整数集 ,则下列各项错误的是 (　　 )(A)M∪ (CZN) =Z .　 (B) (CZM )∩N = .(C)M =N . (D)M∪N =Z .2 .已知a ,b是两个单位向量 ,下列命题中错误的是 (　　 )(A) |a|=|b|.(B)a·b =1.(C)a与b方向相反时 ,a +b =0 .(D)a与b方向相同时 ,a =b .3.设命题 p :3≤ 4 ,q :5 6∈ [6 5 ,+∞ ) ,则三个复合命题 :“p且q” ,“p或q” ,“非 p”中 ,真命题的个数为 (　　 …     

解一个三角形数表题的思维历程

题目给定倒三角形数表如图1所示,其中第一行各数依次是1,2,3,…,2009,从第二行起每一个数分别等于上一行左右两数之和,最后一行只有一个数M,则这个数M是_________．     

整系数多项式的哥德巴赫定理

哥德巴赫猜想断定每一个比4大的偶数是两个素数的和、用Z表示整数环,多项式环Z[x]与Z一样是一个唯一分解整环,其中不可约多项式相当于整数中的素数。本文的目的是证明多项式环Z[x]中与哥德巴赫猜想类似的定理。 定理1.在Z[x]中每一个次数n≥1的多项式M可以写成两个不可约n次多项式A与B的和,即     

Cohomology Complex Projective Space with Actions of G_5

§1. Introduction A cohomology complex projective nspace is a smooth, closed, orientable 2nmanifold M2n such that there is a class x∈H2(M; Z) with the property that H*(M; Z)=z［x］/(xn+1). Let i: K2n-1M2n be the inclusion map of a closed, connected, orientable submanifold and d is an integer; we say that the degree of K2n-2 is d, if i*［K］ is the Poincaré dual of dx. We always assume that the orientation of K2n-2 is chosen in such a way that d is nonnegative. Let p be a prime number…     

导出子图和周长的局部定理

设G是n阶2-连通图，3≤c≤n.本文绘出对于图G的每一个同构于K1.3或Z1的导出子图L，若d（u）且如果dL（u，v）=2有（v）=min{，|M3（u）|/2}这里M3（u）={v|dc（u,v）≤3}，则G包含长至少为c的圈．     

关于p叶解析函数的一个新子类

引进了在单位圆盘E={Z|Z|＜1}内p叶解析函数的一个新子类Mλp(n,α,A,B)(p是正整数,n＞-p的任一整数,-1≤B＜A≤     

扩散过程轨道空间上的对数Sobolev不等式(英语)

设M是连通Riemann流形,Z是M上C′类向量场,L=(△ Z),本文使用Kendall的耦合分析,给出了参考测度为L-扩散过程在t时刻分布的对数Sobolev常数的估计,并由此建立了轨道空间上的对数Sobolev不等式。此外,本文还给出了流形上的对数Sobolev常数的一个上界估计,所获结果,是对文[1],[2]和[3]的相应结果的推广。     

$FI$-$t$-提升模和$t$-quasi-dual Baer模

本文引入$FI$-$t$-提升模和$t$-quasi-dual Baer模的概念并给出两者的联系.证明富足补模$M$为$FI$-$t$-提升模当且仅当$M$的每个完全不变$t$-coclosed子模为$M$的直和项当且仅当$\bar{Z}^{2}(M)$为$M$的直和项且$\bar{Z}^{2}(M)$为$FI$-$t$-提升模当且仅当$M$同时为$t$-quasi-dual Baer 模和$FI$-$t$-$\mathcal{K}$-模.