Matrices - characteristic roots, Cayley–Hamilton theorem, canonical forms under equivalence - One Line Questions
1.
If A is a singular matrix, then at least one of its eigenvalues is: —
0
2.
What is the determinant of a matrix A if λ = 0 is one of its eigenvalues? —
0
3.
If A is an orthogonal matrix, its eigenvalues have absolute value: —
1
4.
The eigenvalues of A = [[2, 1], [1, 2]] are: —
1 and 3
5.
The canonical form under congruence transformation for a real symmetric matrix is: —
A diagonal matrix with +1, -1, and 0 on the diagonal
6.
What is the Smith Normal Form of a matrix? —
A diagonal matrix with invariant factors on the diagonal
7.
What is an eigenvector of a matrix A? —
A non-zero vector v such that Av = λv for some scalar λ
8.
If A is a square matrix, what does the Cayley-Hamilton theorem state about A? —
A satisfies its characteristic polynomial, i.e., p(A) = 0
9.
According to the Cayley-Hamilton theorem, for A = [[2, 1], [1, 2]], we have: —
A² - 4A + 3I = 0
10.
For an n x n matrix A, how many eigenvalues can it have? —
Exactly n
11.
Two matrices A and B are equivalent if there exists an invertible matrix P such that: —
B = PAP⁻¹
12.
Two matrices A and B are similar if there exists an invertible matrix P such that: —
B = P⁻¹AP
13.
Which theorem guarantees that a matrix is a root of its characteristic polynomial? —
Cayley-Hamilton theorem
14.
According to the Cayley-Hamilton theorem, every square matrix satisfies its own: —
Characteristic equation
15.
The set of all matrices equivalent to a given matrix A forms a: —
Class
16.
The set of all matrices similar to a given matrix A forms a: —
Class
17.
What is the characteristic equation of a square matrix A? —
det(A - λI) = 0
18.
If a matrix A is similar to a diagonal matrix D, then A is called: —
Diagonalizable
19.
The scalar λ in the equation Av = λv is called the: —
Eigenvalue
20.
If two matrices are similar, they have the same: —
All of the above
21.
The characteristic roots of a matrix are also known as: —
All of the above
22.
Which of the following is NOT preserved under similarity transformations? —
Rank
23.
The roots of the characteristic equation of a matrix are called: —
Eigenvalues
24.
The canonical form under equivalence is obtained by applying: —
Elementary row and column operations
25.
The Cayley-Hamilton theorem can be used to: —
All of the above
26.
The canonical form of a matrix under equivalence transformation is unique if the matrix is: —
In Smith Normal Form
27.
The canonical form of a matrix under equivalence is determined by its: —
Invariant factors
28.
A matrix A is diagonalizable if and only if: —
Its minimal polynomial has distinct roots
29.
The canonical form under similarity transformation is: —
Jordan Normal Form
30.
If A is an n x n matrix, its characteristic polynomial has a degree of: —
n
31.
According to the Cayley-Hamilton theorem, the characteristic polynomial p(λ) = det(A - λI) satisfies: —
p(A) = 0
32.
If A is a skew-symmetric matrix with real entries, its eigenvalues are: —
Purely imaginary or zero
33.
Which of the following is NOT preserved under equivalence transformations? —
Eigenvalues
34.
If A and B are equivalent matrices, they have the same: —
Rank
35.
If A is a real symmetric matrix, its eigenvalues are: —
Real
36.
The characteristic roots of A and A⁻¹ (if A is invertible) are: —
Reciprocals of each other
37.
The Jordan Normal Form is a canonical form under which transformation? —
Similarity
38.
The canonical form under similarity is obtained by applying: —
Similarity transformations
39.
The set of all eigenvalues of a matrix A is called its: —
Spectrum
40.
If A is a diagonal matrix, its eigenvalues are: —
The diagonal entries
41.
What is the minimum polynomial of a matrix A? —
The monic polynomial of least degree that annihilates A
42.
If A is an n x n matrix, and λ1, λ2, ..., λn are its eigenvalues (counting multiplicity), then tr(A) = Σ(λi) and det(A) = Π(λi). This is a consequence of: —
The properties of characteristic roots
43.
The characteristic polynomial of a 3x3 matrix A is given by -λ³ + tr(A)λ² - (sum of principal minors of order 2)λ + det(A). This is consistent with: —
The properties of eigenvalues and the characteristic equation
44.
The characteristic roots of A and A^T are: —
The same
45.
What is the trace of a square matrix? —
The sum of its diagonal elements
46.
The invariant factors of a matrix are: —
Unique polynomials that are preserved under elementary row and column operations
47.
If A is a nilpotent matrix, then all its eigenvalues are: —
Zero
48.
If A is a 2x2 matrix with eigenvalues λ1 and λ2, then det(A) is equal to: —
λ1 * λ2
49.
If A is a 2x2 matrix with eigenvalues λ1 and λ2, then tr(A) is equal to: —
λ1 + λ2
50.
The characteristic equation of a 2x2 matrix [[a, b], [c, d]] is: —
λ² - (a+d)λ + (ad-bc) = 0