问题 单项选择题

设α1,α2,α3是四元非齐次线性方程组AX=b的三个解,秩(A)=3,k任意实数,则AX=b的通解X=()。

A.α1+k(α123)

B.α1+k(α123)

C.α1+k(2α123)

D.α1+k(3α1-2α2-2α3)

答案

参考答案:C

解析:

由于α123不是AX=0的解,故选项A不正确;由于α123不是AX=0的解,故选项B不正确;

由于3α1-2α2-2α3=2(α12)+(α13)-α3不是AX=0的解,故选项D不正确;

由于2α123=(α12)+(α13)是AX=0的解,秩(A)=3的基础解系由一个解向量组成,故k(α123)是AX=0的通解,故正确答案为C。

综合
填空题


It is clear that we are rapidly becoming a global culture. New forms of information technology, intercontinental travel, and the complex nature of economics are all elements in such a change. Japan, an ancient (1) culture, now dominates the West economically while its own traditional (2) is rapidly becoming (3) in the process.
It does not take a great deal of analysis to see the vast interchanges of cultural influences in the world today. The thirst for (4) fashions, popular music, and the other elements of consumer culture (5) great inroads in non-Western lands while the West seeks out everything from the religious traditions of the Ease (6) the art and music these countries produce. In the field of (7) , to cite one conspicuous example, contemporary readers seek books (8) those of the West. Latin American authors, as well as those from Africa, Asia, and India, now find appreciative audiences.
A (9) culture does not mean a unitary or "one world" culture. It does mean that people are increasingly aware of the diversity of culture. World events enter our living rooms so that things that may once have been (10) of as distant (11) now greet us immediately and in color. We may watch those events on a television made in Japan while wearing clothes sewn in Thailand and shoes made in Hungary while snacking (12) food grown in Mexico. Such an economic interdependence reflects the reality of a global banking system, the globalization of the economy, and the increasing (13) of information and information technologies.
(14) has this shrinking of distances (and attitudes) become more clear than in the academic debates over what constitutes a liberal (15) education today. Is it possible (or desirable) to have the Western core of humanities (16) the center-piece of a curriculum The place of non-Western and non-traditional cultures as part of the general (17) of a student is hotly argued in educational circles. The very fact of that discussion (18) to the emergence of a global consciousness with a continued shrinking of parochial attitudes. The (19) that such globalization is hotly debated only emphasizes the profound nature of the (20) taking place in our culture.