稍懂狭伯虱辰溜谰敬估泞炼滥
Chapter 1 Systems of Linear Equations
unit test 1
1、单选题：
A: 
B: 
C: 
D: 
答案:
2、单选题：
In the following matrices, ( ) is not elementary matrix.
A: 
B: 
C: 
D: 
答案:
3、单选题：
A:
the elementary row operation of interchanging
the first and second rows.
B:
the elementary row operation of interchanging
the second and third rows.
C:
the elementary column operation of interchanging the first and second columns.
D:
the elementary column operation of interchanging the second and third columns.
答案:
the elementary row operation of interchanging
the second and third rows.
4、判断题：
If 
is nonsingular, then can be factored into a
product of elementary matrices.
A: 正确
B: 错误
答案: 正确
5、判断题：
If A is a 3×3 matrix and a1 +2a2 −a3 = 0, then A must be singular.
A: 正确
B: 错误
答案: 正确
6、判断题：
If A and B are n×n matrices, then (A-B)2 = A2 −2AB+B2.
A: 正确
B: 错误
答案: 正确
7、填空题：
Use back substitution to solve the following systems
of equations:
答案: x1 = 4
x2 = 1
x3 = 3
8、填空题：
答案: – 2/3
9、填空题：
答案: 5 -10 15
5 -1 4
8 -9 6
10、填空题：
答案: 1 2 -3
-1 1 -1
0 -2 3
Chapter 2 Determinants
unit test 2
1、单选题：
A: 1
B: 6
C: -6
D: 0
答案: -6
2、单选题：
Let A be a n×n matrix, then ( )
A:
AAT =ATA.
B:
det(AAT ) = det(AT A).
C:
if det(A) = 0, then A is invertible.
D:
if det(A) = 0, then AT is invertible.
答案:
det(AAT ) = det(AT A).
3、单选题：
A: