线性代数矩阵练习题参考答案
线性代数矩阵练习题参考答案
12,1《线性代数》第二章练习题参考答案 AAEO,,,4A满足,则 8、设矩阵()AE,,(2)AE,2
102,,一、填空题 ,,r(A),2r(AB),9、设A是矩阵且,,则 2 4,3B,020,, ,,,103123,2927032,,,,,,,,,,,,TB,1、设,,则 3A+2B =; AB
=; ,,,,A,B,,,,,,,,,,,21,1335111,21,,,,,,,,,,100100,,,,,,11,,,,110、设,则 A,220(A),A,220,,193,,,,,,A10,,,,,,,,1531614,,,,,,34534588,1,,,,2、设矩阵。 ABABAB,,,,,,,则,
3,,,,,,,,13205911,,,,,,,,,,,100,,88,,300,,,,,,11,1,,,011、设,则 (用分块矩阵求逆矩阵) A,140(2)AE,,27,,*,12A,A,AA,23、设为三阶矩阵,且,
则 ,,22,,2003,,,,001,,
…………………………………………………… ……………………………………………………4、设矩阵A为3阶方阵,且|A|=5,则|A*|=__25____,
|2A|=____40_ 1200,,,
,,班级: 姓名:学号:5200,,,2500装订线
________________________________________ 密封
线,,120,,86,,,,,,210023,1,,,,,,,1,,12TA,12、设,则 A,ABA,3403、设,,,,则=
B,181000,,,, ,,,,,,001,2,24033,,,,,,,,,,,121310,,,,,,001111,,,,…………………………………………………………00,,,33,,111,,,,r(A),24、设,且,则4 A,225t,,,132A13、已知为四阶方阵,且,则 A,,,11t281,,
1233,,2n,1,,,,,,,,2222,,0312,,,,,,,,,n,,,1,12n25、若A= 则
r(A)=_2____ AA,33314、设,=,
AA,,3,,,,,0624,,,,,,,,12n,,,,,,,,,,44440000,,,,,,,,,,
1,,10018001800,,,,,,1,1,,0,12,,1B,,,BAAE,,,326、设矩阵,,则A,,,,,,,,12,,,A15、若,= ,1260,,,,则
AA2301260,,23,,,,,,,,18,,11,,,,,,,,,,253456253,,,,,,,,
2,1AAEO,,,22…………………………………………………………A7、设是方
阵,已知,则3EA, ()AE,,二、单项选择题
2 1AA,1、若,则下列一定正确的是 ( D ) n,1naa; (B); (C); (D)。
(A)aaAA,,,,或(A) (B) A,, (C) (D)以上可能均不成立 A,,
aaaaaa,,,,A,B2、设为阶矩阵,下列命题正确的是 ( C ) n111213111213,,,, A,aaa,B,a,aa,aa,a,,,,,212223113112321333222229、设 (A); (B); (A,B),A,2AB,B(A,B)(A,B),A,B,,,,aaaaaa313233212223,,,,
2222(C); (D)。 AEAEAE,,,,()()(AB),AB
A3、设是方阵,若,则必有 ( C ) AB,AC100100,,,,,,,,
C,001,D,010 ,则必有( C ) ,,,, (A)时; (B)时;
A,0B,CB,CA,0,,,,010101,,,,
A,0A,0 (C)时; (D)时. B,CB,C
(A) ACD=B ; (B)ADC=B; (C) CDA=B; (D) DCA=B 4、下列矩阵为初等矩
阵的是 ( A )
三、解答题…………………………………………………… ……………………………………………………100312,,,,001100,,,,,,,,,,,,(A)010 (B) (C)(D) 000012123班级: 姓名:学号:,,,,1111,,,,,,装订线 ________________________________________
密封线223,,,,,,,,,,,,001100,,,,012231,,11,1,1,,,,,,,1AA,1,101、
求:(1);(2) A,,, ,,1,11,1,,,,AB5、设、为同阶方阵,且,则必有 ( C )
AB,O,121,,,,1,1,11,,…………………………………………………………
(A)或; (B); A,OB,OA,B,O1111,,
,,4444(C)或; (D)A,B,O。 A,OB,O,,1111,,143,,,,,,,,4444,,,1,1AB6、、为同阶方阵,则下列式子成立的是 ( C ) A,(1), (2)
A,,,153,,,,1111,,,,,,,164,,AB,BA(A); (B); A,B,A,B,,4444 ,,1111,1,1,1,,,,(C)AB,BA; (D) 。 (A,B),A,B,,4444
10010,,,,ABCABCE,7、设n 阶方阵、、满足关系式,则有 ( D ) ,,,,-
1A,,1102、若AX = B,其中,,求(1)A;(2)X B,01,,,,
,,,,ACBE,CBAE,BACE,BCAE,(A);(B);(C);(D) 12,120,,,,
…………………………………………………………,A,AA,a,08、设为n 阶方阵,且,则 ( C )
,12k,1k 10010,,,,,其中k为正整数,证明: 1、设(E,A),E,A,A,??,AA,0,,,,,1,1, A,110XAB,,11,,,,21kkkk,,,,,因为
()()EAEAAAEAEoE,,,,,,,,,,321,12,,,,
3、解矩阵方程 ,12k,1由定义 (E,A),E,A,A,??,A
13,,2,1,1,,21,,2、设方阵A满足A-A-2E=O,证明A及A+2E都可逆,并求 A 及(A,2E),,X,20 ,求 X,?,,,,53,,,,311,,22,,AAEE,,证明 (1)由A-A-2E=O,得A-A=2E,A(A-E)=2E, ,,,,2,,13,,2131,,,,,,,,11解:设,
AB,,,20A,,1,,,,,,所以 A可逆,且 ,,AAE,,53,52,,,,,,231,, 2213125,,,,,(2)由A-A-2E=O,得A-A-6E=-4E,于是(A+2E)(A-3E)=-4E,所以31,,,,,,,,1
XBA,,,,2062,,,,,,,52,,11,,,,,,,1…………………………………………………… ……………………………………………………3141,()A2EA3EE,,,-,因而
A+2E可逆,且 (),,,-A2EA3E,,,,,,,,,,44,,11,1,,班级: 姓名:学号:装订线,, ________________________________________ 密封线2AAXE,,A4、设且,求矩阵 A,011,,
,, 00,1,,
,1AXA,,AAXE(),,,解: ,…………………………………………………………
111,110021,,,,,,,,
,,,,,,,1XAA,,= 011,,011000,,,,,,,,,,,,001,001000,,,,,,,
*A,8AA5、设是4阶实矩阵,且,求 A=2
,1,(3A),2AA6、设为三阶方阵,且A,2,求
311,1,(3A),2A,,= 54
…………………………………………………………四证明题: