Homework # 8 - Math 241
The problems on this homework must be done alone. The honor code is in effect.
First name: Last name:
1. Say \(A\) is a 5 by 8 matrix. If the dimension of Row(A) is 2, what is the dimension of Col(A)?
a. 2
b. 3
c. 5
d. 6
2. Say \(A\) is a 5 by 8 matrix. If the dimension of Row(A) is 2, what is the dimension of Nul(A)?
3. Find all the eigenvalues of the matrix $$A = \left[\begin{array}{cc} 1 & 2\\ 2 & 4\end{array}\right]$$
a. 0 and 5
b. 0 and 1 and 2
c. 1 and 5
d. 1 and 2 and 4
For questions 4 through 6, let $$A = \left[\begin{array}{cccc} 1 & 2 & 3 & 4\\ 0 & 1 & 2 & 0\\ 0 & 0 & 2 & 1\\ 0 & 0 & 0 & -2\end{array}\right]$$
4. Find the eigenvalues for \(A\).
a. 1, 2, 3, 4
b. 0, 1, 2, 3, 4
c. -2, 0, 1, 2, 3, 4
d. -2, 1, 2
e. 0, 1, 2
5. Describe the eigenspace for \(\lambda = 1\).
a. A line through the origin
b. Two lines through the origin
c. A plane through the origin
d. All of \(R^4\)
e. Just the zero vector
6. Which of the standard unit basis vectors are eigenvectors for \(A\).?
a. Just \(e_1\)
b. Just \(e_4\)
c. All of them.
d. None of them.