共查询到19条相似文献，搜索用时 421 毫秒
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张瑞林 《陕西理工学院学报(社会科学版)》2000,(3)
证明了FBZ-代数按所规定的偏序 ,确实是一偏序集 ,即若X是FBZ-代数 ,则 x∈X ,x≤x.讨论了FBZ-代数与BCI_代数的关系 .证明了满足条件x (yz) =y (xz)的FBZ_代数 ,如果令 X =X ,x y=yx ,0 =1,则 ( X , ,0 )一定是BCI-代数 ;反过来 ,若 (X , ,0 )是BCI-代数 ,令 X =X ,xy =y x ,1=0 ,则 ( X , ,1)是FBZ-代数 .还引入了正则FBZ -代数的概念 ,给出了正则FBZ-代数的一个特性 . 相似文献
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复数是高中代数的重要内容 ,由于它有多种表示方法 (代数法、三角法和指数法等 ) ,能将代数、三角、几何等知识紧密地联系起来 ,因此 ,在数学竞赛中常有有关复数的考题 .另外 ,复数本身也可作为一种方法 ,运用复数法可以解决函数最值、三角恒等式、组合问题、不等式问题、数列问题等 .1 求函数最值例 1 若 x,y,z∈ ( 0 ,+∞ ) ,且 x+ y+ z= 1 ,求 u=x2 + y2 + xy + y2 + z2 + yz+x2 + z2 + xz的最小值 .略解 令 z1 =( x+ 12 y) + 32 yi,z2 =( y+ 12 z) + 32 zi,z3=( z+ 12 x) + 32 xi,∴ u=| z1 | + | z2 | + | z3|≥ | z1 + z2 + z3|=3.… 相似文献
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在△ABC中引入代换:a=y+z,b=z+x,c=x+y于是可得三内角的一系列代数关系式:cosA=(b~2+c~2-a~2)/2bc=(x(x+y+z)-yz)/(z+x)(x+y)=1-(2yz)/(x+y)(x+z). 相似文献
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徐培月 《中学数学教学参考》1994,(3)
初三复习中,有些题目难度虽不大,但由于考虑不周密,解答中却常出现错误,现举例如下: 例1 已知(x y):z=(y z):x=(x z):y=k,求k的值. 误解:k=(x y):z=(y z):x=(x z):y=2(x y z):(x y z)=2。 解题过程似乎无懈可击,但此题实有两解,漏解原因在于解题中应用等比定理,把x y z当作不等于0的式子,而忽略了x y z=0的情况。 当x y z=0时。x y=-z;y z=-x;x z=-y;所以k=-1。 所以,本题有两解k=2或-1。 相似文献
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李金龙 《陕西理工学院学报(社会科学版)》2001,(3)
给出了两种求广义结合BCI_代数商代数的十分方便的方法 ,即 :设H为广义结合BCI_代数X的子代数 ,(1 ) x∈X ,令xH ={x h|h∈H} ,X/H ={xH|x∈X} ,定义xH yH =(x y)H ,则 (X/H ; ,0H)是广义结合BCI_代数 ;(2 ) x∈X ,令Hx={ (x h) h|h∈H} ,X/H2 ={Hx|x∈X} ,定义Hx Hy=Hx y,则 (X/H2 ; ,H0 )是广义结合BCI_代数 . 相似文献
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引入比BCI-代数条件更弱的四种弱BCI-代数,讨论它们的等价条件,并给出弱BCI-代数的一种二元运算“＋”：x＊y=x＋（x＊y）,讨论了与这种运算相关的可分配性,进而四种弱BCI-代数在可分配下得到统一． 相似文献
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多项式护 y“十z“一3xyz分解方法如下: x“ y3=(x Jr)3一3xy(x y) (x y)3 23=(x y z)〔(x y)2一(x y)z 22〕 故有x3 y3 23一3xyz=(x y)3一3xy(x y) 23一3xyz =(x y z)〔(x y)2一(x y)z 22〕一3xy(x y z) =(x y z)(xZ yZ 22一xy一yz一xz) 即:x3七y3 23一3xyz=(x 了 z)(xZ yZ 22一xy一yz一xz) 如在复数范围内还可继续分解为: x3 y3 23一3xyz=(x y z)(x 。y 。22)(x 。Zy 。z) .。是1的三次虚根(1)式是个很重要的公式,应用广泛,现仅举几例说明之。 1.因式分解 公式(1)中如果x y z=0,则(1)式变为 x3 y3 23二3xyz(3)式说明:任意三数之和如为0… 相似文献
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代数、几何,三角中有一类题目,若利用等比定理来解,则可以使解题过程大大简化,请看下面数例: 例1 若(x(y+z-x))/(log_αx)=(y(z+x-y))/log_αy=(z(x+y-z))/(log_αz)。求证:y~zz~y=z~xx~z=x~yy~x。证明:∵(y+z-x)/((1/x)log_αx)=(z+x-y)/((1/y)log_αy)=(x+y-z)/((1/z)log_αz)。两次运用等比定理得 相似文献
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有关证明条件等式的代数题,是一类综合性比较强的题目,如果能让学生掌握其各种不同的证明方法,对于培养他们的逻辑思维能力和熟练的技能技巧都是大有益处的。下面介绍几种证明条件等式的常用方法。一、将已知条件直接代入欲证等式例1 已知:x=(a-b)/(a b),y=(b-c)/(b c), z=(c-a)/(c a) 求证:(1 x)(1 y)(1 z) =(1-x)(1-y)(1-z) 证明:∵(1 x)(1 y)(1 z) =(1 (a-b)/(a b))(1 (b-c)/(b c))(1 (c-a)/(c a)) =2a/(a b)·2b/(b c)·2c/(c a) (1-x)(1-y)(1-z) =(1-(a-b)/(a b))(1-(b-c)/(b c))(1-(c-a)/(c a)) =2b/(a b)·2c/(b c)·2a/(c a) ∴ (1 x)(1 y)(1 z)=(1-x)(1-y)(1-z) 二、通过已知条件之间的相互变换,得出求证式。例2.设x=by cz,y=cz ax,z=ax by 试证:(a 1)x=(b 1)y=(c 1)z 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献