电子科技大学研究生试卷
(考试时间:10:00-12:00 共:2 小时)
课程名称:矩阵理论 教师:刘福体 学时:60 学分:3 教学方式:堂上教学 考试日期:2014年12月31日 成绩:
考核方式: (学生选填)一、 选择题(每题4分,共20分) 1、若A B 、为n 阶方阵,下列结论错误的是····································································( ) A. (A B)H H H A B ?=? B. det(A )det(A)det(B)B ?= C .tr(A B)()()tr A tr B ?= D. (A B)A B +++?=?
2. A 是正规矩阵,则下列说法错误的是········································································( )
A. A 的不同特征值对应的特征向量正交
B. A +
是正规矩阵
C .A 的特征值为A 的奇异值 D. 若A 的特征值为i λ,则2
2
1
||||||
n
F
i
i A λ==∑
3. 下列命题错误的是········································································································ ( ) A.AB AC A AB A AC ++
=?=
B. rank(AB)rank(A)=,则(AB)R(A)R =。
C .A 正规,则A 的特征向量也是H
A 的特征向量。 D. 2
A A =,且A BC =,则C
B E =(单位矩阵)。
4. 设012c A c ???
?=???
?
,若0
k k A ∞
=∑收敛,则c 为··································································( ) A.1
2
c ≥
B.|c|1≥
C. |c|1≤
D.|c|<1 5.下列结论正确的是············································································································( ) A. (AB)B A +
+
+
= B. 2
21
||A||n
F
i
i σ
==
∑
C .(A)rank(A )rank +
= D. (A )A --
=
二、计算和证明(共80分) 1、(9分)设n n
A B C ?∈、,证明:222||AB||||A ||||B||m m m ≤
2、(9分)设(a )C n n ij A ?=∈既是正规矩阵,又是上三角矩阵,证明:A 一定是对角矩阵。
3、(8分)求矩阵1141A ??
=????
的谱分解。
4、(8分)设(a )C
n n
ij A ?=∈,证明:A 的任一特征值
1
n
i i S S λ=∈=
,其中
{z C :|z a |R
|a
i i i i i j
j i
S ≠=∈-<=∑ .
5.(8分)若3113A ??
=????
,计算sin(A).
6.(8分)设A 是秩为1的n 阶矩阵,(A)tr 为A 的迹。证明:1()n n A trA A -=.
7.(8分)设m n
A C ?∈,证明:22||A A ||m m +=.
8.(15分)已知011101110011A -????-?
?=??-??-?? ,1101b ????
-??=??????
。 (1)求矩阵A 的最大秩分解; (2)求A +
;
(3)判断方程组Ax b = 是否有解;
(4)求方程组Ax b =的最小范数解及通解或最小二乘解通解及最佳范数解?(指出所求的是哪种解)
9.若m n
A C
?∈,A -是A 的广义逆矩阵,则A -
是A 的自反广义逆矩阵的充要条件是
(A)rank(A )rank -= 。