设A为m×n实矩阵，E为n阶单位矩阵，已知矩阵B=λE+ATA，试证：当λ＞0时，矩 发布时间：2018-05-28 12:24 │ 来源：www.tikuol.com 题型：问答题 问题： 设A为m×n实矩阵，E为n阶单位矩阵，已知矩阵B=λE+ATA，试证：当λ＞0时，矩阵B为正定矩阵．
题型：问答题 短文改错。此题要求改正所给短文中的错误。对标有题号的每一行做出判断∶ 如无错误,在该行右边横线上画一个勾(√)；如有错误(每行只有一个错误)，则按下列情况改正∶该行多一个词∶ 把多余的词用斜线（\）划掉, 在该行右边横线上写出该词，并也用斜线划掉。该行缺一个词∶ 在缺词处加一个漏字符号(∧)，在该行右边横线上写出该加的词。该行错一个词∶ 在错的词下划一横线，在该行右边横线上写出改正后的词。注意∶ 原行没有错的不要改。 Get a good education is more important today than ever before. In Canada mostly children attend public schools. Public schools are mainly found by governments through tax income. Students in Canada taught in English and in French. The rests of Canadian children attend private schools, that are supported mainly by fees paying by parents. By law, the children must attend the school from age 5 to 16. There are several different levels in the Canadian education system .The first was called Elementary Schools, which include kindergartens through grade 7 or 8. 1._______________ 2._______________ 3._______________ 4._______________ 5._______________ 6._______________ 7._______________ 8._______________ 9._______________ 10._______________ 查看答案
题型：问答题 An investor has a $15000 portfolio consisting of $10000 in stock A with an expected return of 20 percent and $ 5000 in stock B with an expected return of 10 percent. What is the investor's expected return on the portfolio（）A.7.9%.B.12.2%.C.16.7%. 查看答案