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刘明贤 《河南广播电视大学学报》1996,(1)
矩阵方程的初等行变换解法刘明贤在现行线性代数教材中．解矩阵方程ＡＸ—Ｂ或ＸＡ—Ｂ，都是通过求矩阵Ａ的道的方法解出未知数矩阵Ｘ。这种方法不仅运算繁冗，而且当Ａ不是方阵时，还不能用此法求解。本文试图用初等行变换法（约定在施行变换过程中，不互换两行的位置）... 相似文献
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矩阵方程ＡＸ＝Ｂ（或ＸＡ＝Ｂ）,当Ａ可逆时,一般解法是：（１）求Ａ－１;（２）计算Ａ－１Ｂ（或ＢＡ－１）即为其解。这种方法虽然思路自然,现用教材大多采用这种解法。但运算较繁。其实稍加改进便可得到自然而简捷的方法。当Ａ可逆时,矩阵方程ＡＸ＝Ｂ的解为：Ｘ＝Ａ－１Ｂ。因为Ａ－１（Ａ∶Ｂ）＝（Ｅ∶Ａ－１Ｂ）,又因Ａ－１可逆,所以,Ａ－１＝Ｐ１Ｐ２…Ｐｎ。其中Ｐ１,Ｐ２,…,Ｐｎ为初等矩阵,Ａ－１左乘矩阵（Ａ∶Ｂ）施行行的初等变换将Ａ化成Ｅ的同时,就可以将Ｂ化成Ａ－１Ｂ,即为矩阵方程的解。例如：解矩阵方程… 相似文献
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(一)填空题12-101-4000-1=。2若Ａ为3×4矩阵,Ｂ为2×5矩阵,且乘积ＡＣ′Ｂ′有意义,则Ｃ为矩阵。3设二阶矩阵Ａ=11015=。4设Ａ=1240-34,Ｂ=-1203-14,则(Ａ Ｂ′)′=。5设Ａ,Ｂ均为3阶矩阵,且Ａ=Ｂ=-3,则-2ＡＢ=。6矩阵2-124020-33的秩为。7ｎ 1个ｎ维向量组成的向量组一定线性。8若线性方程组ＡｍｎＸｎ1=Ｂｍ1有解的充分必要条件是。9齐次线性方程组ＡｍｎＸ=0的系数矩阵ｒ(Ａ)<ｎ,则方程组的基础解系中解向量个数为。10若Ａ,Ｂ为两事件,且Ｐ(Ａ)>0,Ｐ(Ｂ|Ａ)=Ｐ(Ｂ),则Ａ与Ｂ。11若Ｘ～Ｂ(ｎ,ｐ)且Ｅ(Ｘ)=6,Ｄ(Ｘ)=36,则ｎ=。12设Ａ,Ｂ为… 相似文献
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利用矩阵的广义逆及奇异值分解，给出了子矩阵约束下线性矩阵方程XA＝B有对称非负定解的充分必要条件，并在有解时，给出了相应解的一般表达式。 相似文献
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在ＧＭＡＮＯＶＡ－ＭＡＮＯＶＡ模型中，对于指定的非负定矩阵Ｃ，本文给出了ｔｒ（Ｃ∑）是ｔｒ（Ｃ∑）的一致最小方差非负二次无偏估计的充要条件，这里∑是∑的（一定意义下的）最小二乘估计。 相似文献
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本文研究了任意体上的矩阵方程「ＸｎｎＡｍ,ＸｎｎＢｎｔ」＝「Ａｎｓ,Ｏ」,给出了（Ⅰ）的相容的充要条件、通解的显式表示,解的性质及其实用解法,通常意义下的投影矩阵在任意体上也得到了进一步的推广。 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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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献