Math 203 2008 Fall Exam 2
1. Find the determinant of the matrix
"1−2
3 4 #
10
2. (continued) The (1,2)-th element of the inverse of the above matrix is
1/5
3. Find the determinant of the matrix
−1 2 2 4
1−2−3 0
0 0 −1 2
1 2 3 4
−8
4. The determinant of the following matrix is 60. Find the (2,3)-th ele-
ment of its inverse.
1a3
3 4 −1
1 2 b
1/6
5. Denote by Eathe elementary matrix
1 0 0 0
0 1 0 0
0a1 0
0 0 0 1
The inverse of E2is
E−2
6. Let
A=
1 2 3 4
0 1 0 0
2 1 3 1
a b c d
, B =
1 2 3 4
0 1 0 0
3 2 4 1
a b c d
1
