ThatQuiz Test Library Take this test now
Matrix (mathematics) - Quiz
Contributed by: Heaton
  • 1. What is a matrix in mathematics?
A) A rectangular array of numbers or other mathematical objects
B) A three-dimensional cube of numbers
C) A circular array of numbers
D) A single linear sequence of numbers
  • 2. How are the elements of a matrix arranged?
A) In rows and columns
B) In hierarchical trees
C) In concentric circles
D) In random clusters
  • 3. What do we call a matrix with two rows and three columns?
A) A 3 by 2 matrix
B) A 2 by 3 matrix
C) A square matrix
D) An empty matrix
  • 4. In linear algebra, what are matrices primarily used as?
A) Geometric points
B) Prime numbers
C) Probability distributions
D) Linear maps
  • 5. How are matrices used in geometry?
A) To measure lengths of curves only
B) For geometric transformations and coordinate changes
C) To define continuous functions
D) To calculate the area of circles
  • 6. What type of matrices play a major role in matrix theory?
A) Infinite matrices
B) Empty matrices
C) Row matrices
D) Square matrices
  • 7. What is the determinant associated with?
A) A row vector
B) A square matrix
C) An infinite matrix
D) An empty matrix
  • 8. When is a square matrix invertible?
A) If and only if its determinant is zero
B) If and only if it has more rows than columns
C) If and only if all its entries are negative
D) If and only if it has a nonzero determinant
  • 9. What are the eigenvalues of a square matrix?
A) The number of rows it contains
B) The sum of its diagonal entries
C) The product of its dimensions
D) The roots of its characteristic polynomial
  • 10. What does matrix theory currently focus on besides linear algebra?
A) Graph theory, algebra, combinatorics, and statistics
B) Quantum mechanics exclusively
C) Fluid dynamics and thermodynamics
D) Calculus, topology, and number theory only
  • 11. What are the numbers or objects in a matrix called?
A) Factors or multiples
B) Entries or elements
C) Nodes or vertices
D) Roots or powers
  • 12. What are the horizontal lines of entries in a matrix called?
A) Vectors
B) Columns
C) Rows
D) Diagonals
  • 13. What are the vertical lines of entries in a matrix called?
A) Diagonals
B) Scalers
C) Columns
D) Rows
  • 14. How is the size of a matrix defined?
A) By the sum of all its entries
B) By the value of its determinant
C) By the largest number in the matrix
D) By the number of rows and columns it contains
  • 15. What restriction applies to the number of rows and columns in a matrix?
A) They must be equal
B) They must be positive integers
C) They must be even numbers
D) They must be prime numbers
  • 16. What is a matrix with m rows and n columns called?
A) An m by n matrix
B) A square matrix
C) An n by m matrix
D) An infinite matrix
  • 17. What do we call matrices with a single row?
A) Column matrices
B) Diagonal matrices
C) Row matrices or row vectors
D) Square matrices
  • 18. What do we call matrices with a single column?
A) Row matrices
B) Square matrices
C) Column matrices or column vectors
D) Empty matrices
  • 19. What is a matrix with an infinite number of rows or columns called?
A) An infinite matrix
B) A limitless matrix
C) A giant matrix
D) An undefined matrix
  • 20. What is a matrix with no rows or no columns called?
A) A blank matrix
B) A zero matrix
C) A null matrix
D) An empty matrix
  • 21. In what context might an empty matrix be useful?
A) Geometric drawing by hand
B) Manual arithmetic calculations
C) Computer algebra programs
D) Physical measurement
  • 22. How are matrices commonly enclosed in symbolic notation?
A) Square brackets or parentheses
B) Curly braces or angle brackets
C) Double vertical bars
D) Single vertical bars
  • 23. How are matrices usually symbolized?
A) Using upper-case letters
B) Using lower-case Greek letters
C) Using symbols like asterisks
D) Using numbers
  • 24. How are individual entries of a matrix usually symbolized?
A) Using upper-case letters with exponents
B) Using Roman numerals
C) Using corresponding lower-case letters with two subscript indices
D) Using bold numbers
  • 25. What is an alternative typographical style used to symbolize matrices?
A) Boldface roman
B) Underlined lowercase
C) Superscripted text
D) Italicized lowercase
  • 26. What is another alternative notation for naming a matrix variable?
A) A double-underline with the variable name
B) A dashed box around the letter
C) A circle surrounding the letter
D) A tilde above the letter
  • 27. What does the entry notation $a_{i,j}$ represent?
A) The product of dimension i and j
B) The entry in the ith row and jth column
C) The determinant of the submatrix
D) The sum of row i and column j
  • 28. What is the set of all m-by-n real matrices often denoted as?
A) Sq(m, n)
B) R(m, n)
C) Mat(R)
D) M(m, n)
  • 29. How is the set of all square n-by-n matrices over a ring R typically denoted?
A) Mat(n, R, m)
B) M_n(R)
C) F_n(R)
D) R_n(M)
  • 30. How are matrix addition and subtraction calculated?
A) Columnwise from right to left
B) By multiplying determinants
C) Entrywise
D) Using row reduction
  • 31. What is the term for the number c when multiplying it by a matrix A?
A) Vector
B) Scalar
C) Matrix
D) Tensor
  • 32. What is the result of scalar multiplication called?
A) cA
B) Dot product
C) Inner product
D) Scalar product
  • 33. What is 'scalar product' often used as a synonym for?
A) Matrix addition
B) Scalar multiplication
C) Inner product
D) Matrix subtraction
  • 34. What is the notation used for the transpose of matrix A?
A) A*
B) AT
C) |A|
D) A-1
  • 35. What is the result of taking the transpose of a matrix twice, i.e., (AT)T?
A) AT
B) -A
C) A
D) 2A
  • 36. Which of the following expresses the compatibility of the transpose with matrix addition?
A) (A + B)T = A + BT
B) (A + B)T = AT + BT
C) (A + B)T = AT + B
D) (A + B)T = ATBT
  • 37. Matrix multiplication corresponds to what concept regarding linear transformations?
A) Inversion
B) Transposition
C) Addition
D) Composition
  • 38. Which property does matrix multiplication satisfy?
A) Commutativity
B) Division
C) Associativity
D) Invertibility for all matrices
  • 39. Is matrix multiplication generally commutative?
A) Yes
B) Only for non-square matrices
C) Only when matrices are zero
D) No
  • 40. Which equation correctly represents the associativity of matrix multiplication?
A) AB + C = A + BC
B) (AB)C = (AC)B
C) A(BC) = (BA)C
D) (AB)C = A(BC)
  • 41. Which equation represents left distributivity of matrix multiplication over addition?
A) (A + B)C = AC + BC
B) C(A + B) = AC + CB
C) (A + B)C = AB + C
D) C(A + B) = CA + BC
  • 42. In solving which type of equation do the Hadamard and Kronecker products arise?
A) Differential equation
B) Linear algebraic equation
C) Sylvester equation
D) Quadratic equation
  • 43. In row multiplication, all entries of a row are multiplied by what kind of constant?
A) Any constant including zero
B) A fractional constant only
C) A negative constant
D) A non-zero constant
  • 44. Which method uses row operations to find matrix inverses?
A) Gauss–Jordan elimination
B) Gauss elimination
C) LU decomposition
D) Cramer's rule
  • 45. Which method uses row operations to solve linear equations?
A) Determinant expansion
B) Gauss–Jordan elimination
C) Gauss elimination
D) Matrix inversion
  • 46. What is another name for a principal submatrix where the first k rows and columns remain?
A) Minor submatrix
B) Leading principal submatrix
C) Diagonal submatrix
D) Identity submatrix
  • 47. A 2 by 2 matrix can be viewed as the transform of the unit square into what geometric shape?
A) A rectangle
B) A rhombus
C) A trapezoid
D) A parallelogram
  • 48. If matrix B is k-by-m and represents a linear map g from Rm to Rk, and A is m-by-n representing f, what matrix represents the composition g circle f?
A) A + B
B) AB
C) B - A
D) BA
  • 49. Equivalently, the rank of a matrix is the dimension of what feature of its represented linear map?
A) The domain
B) The kernel
C) The image
D) The codomain
  • 50. What do the entries aii form in a square matrix?
A) The identity section
B) A scalar multiple
C) The main diagonal
D) An upper triangular part
  • 51. Where does the main diagonal lie in a square matrix?
A) Along the bottom row
B) On the line running from the bottom left to the top right
C) On the imaginary line running from the top left corner to the bottom right corner
D) Along the rightmost column
  • 52. Square matrices of a given dimension form what algebraic structure?
A) An integral domain
B) A linear vector space
C) A commutative field
D) A noncommutative ring
  • 53. What condition defines a skew-symmetric matrix?
A) AB = I
B) A = AT
C) A* = A
D) A = -AT
  • 54. What does the star or asterisk denote in matrix notation?
A) Inverse matrix
B) Determinant
C) Conjugate transpose
D) Regular transpose
  • 55. What theorem states that real symmetric matrices and complex Hermitian matrices have an eigenbasis?
A) Gaussian elimination
B) Invertible matrix theorem
C) Quadratic form theorem
D) Spectral theorem
  • 56. What can be said about the eigenvalues of real symmetric and complex Hermitian matrices?
A) All eigenvalues are negative
B) All eigenvalues are zero
C) All eigenvalues are real
D) All eigenvalues are complex
  • 57. What is another term for an invertible square matrix?
A) Singular
B) Skew-symmetric
C) Non-singular
D) Indefinite
  • 58. What notation is used for the inverse matrix of A?
A) A*
B) AT
C) A-1
D) An
  • 59. What type of symmetric real matrix yields a positive value for the associated quadratic form for every nonzero vector?
A) Skew-symmetric
B) Positive-definite
C) Negative-definite
D) Indefinite
  • 60. What term describes a symmetric matrix whose quadratic form yields only non-negative values?
A) Negative-semidefinite
B) Positive-definite
C) Positive-semidefinite
D) Negative-definite
  • 61. In the case of complex matrices, what replaces the transpose xT in the bilinear form?
A) Conjugate transpose xH
B) Identity vector xi
C) Inverse transpose x-1
D) Negative transpose -xT
  • 62. What is the name of the form associated to A when allowing as input two different vectors?
A) Bilinear form
B) Hermitian form
C) Sesquilinear form
D) Quadratic form
  • 63. Is an orthogonal matrix necessarily invertible?
A) Yes
B) Only for non-square matrices
C) Only if the determinant is zero
D) No
  • 64. What does a special orthogonal matrix represent as a linear transformation?
A) Pure reflection without rotation
B) Scaling
C) Pure rotation without reflection
D) Shear mapping
  • 65. What does an orthogonal matrix with a determinant of -1 do to orientation?
A) Reverses the orientation
B) Doubles the orientation
C) Preserves the orientation
D) Destroys the orientation
  • 66. What equation demonstrates that an orthogonal matrix is normal?
A) det(A) = 1
B) A*A = AA*
C) AT A = I
D) A = A-1
  • 67. What is a nonzero vector v satisfying Av = lambda v called?
A) Determinant
B) Matrix product
C) Eigenvector
D) Eigenvalue
  • 68. What is lambda called when Av = lambda v and v is a nonzero vector?
A) Eigenvalue
B) Eigenvector
C) Characteristic polynomial
D) Zero matrix
  • 69. Eigenvalues of a matrix with real entries can be of what type?
A) Always zero
B) Undefined
C) Always real
D) Complex
  • 70. Matrix calculations can often be performed using direct algorithms and what other approach?
A) Static approaches
B) Recursive approaches
C) Random approaches
D) Iterative approaches
  • 71. Determining the complexity of an algorithm involves finding estimates of how many what are necessary?
A) Determinants
B) Sparse entries
C) Eigenvalues
D) Elementary operations
  • 72. Which algorithm outperforms the naive matrix multiplication algorithm by needing only n to the power of 2.807 multiplications?
A) Conjugate gradient method
B) Cayley-Hamilton algorithm
C) Strassen algorithm
D) MapReduce algorithm
  • 73. What distributed computation systems or parallel algorithms can provide speedups for matrix multiplication?
A) Adjunc
B) MapReduce
C) Eigen-solver
D) Numerical linear system
  • 74. Computing the inverse of a matrix using its adjugate matrix is given by which formula?
A) adj(A) / det(A)
B) det(A) / adj(A)
C) A times det(A)
D) A - lambda In
  • 75. What is a matrix called if it can be written in the form VDV-1?
A) Ill-conditioned
B) Triangular
C) Unitary
D) Diagonalizable
  • 76. What algorithm can be employed to avoid numerically ill-conditioned situations?
A) Gaussian elimination
B) Schur decomposition
C) LU decomposition
D) Jordan decomposition
  • 77. It is possible to consider matrices with how many columns and rows?
A) Infinitely many
B) At most one thousand
C) Only finite numbers
D) Exclusively square dimensions
  • 78. What are higher-dimensional arrays of numbers called, as an extension of matrices?
A) Tensors
B) Scalars
C) Vectors
D) Determinants
  • 79. In general, matrices over any ring and their multiplication can be represented as arrows and composition in what?
A) A group
B) A category
C) A field
D) A vector space
  • 80. What is a set where addition, subtraction, multiplication, and division operations are defined and well-behaved called?
A) A field
B) A group
C) A ring
D) A module
  • 81. What type of entries are widely used in mathematics alongside numbers?
A) Categories
B) Tensors
C) Vectors
D) Polynomials
  • 82. What algebraic notion is more general than fields because division need not exist?
A) Matrix fields
B) Categories
C) Vector spaces
D) Rings
  • 83. What must be chosen before a linear map between finite-dimensional vector spaces can be described by a matrix?
A) Scalars
B) Bases
C) Eigenvalues
D) Determinants
  • 84. What is a mathematical structure consisting of a set of objects and a binary operation subject to certain requirements?
A) A determinant
B) A matrix
C) A group
D) A representation
  • 85. Every matrix group of degree n is a what of the general linear group of degree n?
A) Transpose
B) Determinant
C) Subgroup
D) Supergroup
  • 86. What are orthogonal matrices with a determinant of 1 called?
A) The symmetric group
B) The special linear group
C) The special orthogonal group
D) The general linear group
  • 87. What more powerful tools are often used instead of the explicit point of view of infinite matrices?
A) Combinatorial topology
B) Elementary algebra
C) Arithmetic geometry
D) Functional analysis
  • 88. Which identity is the value of the 0 × 0 matrix determinant needed to be consistent with?
A) The functional analysis identity
B) The Leibniz formula
C) The Desnanot–Jacobi identity
D) The commutative monoid identity
  • 89. What algebraic structure do matrices of fixed size with entries in a semiring form under addition?
A) A Hilbert space
B) A field
C) A semiring
D) A commutative monoid
  • 90. What algebraic structure do square matrices of fixed size with entries in a semiring form under addition and multiplication?
A) A commutative monoid
B) A group
C) A semiring
D) A vector space
  • 91. Over which permutations is the positive determinant summed?
A) Odd permutations
B) Even permutations
C) Finitary permutations
D) All permutations
  • 92. Over which permutations is the negative determinant summed?
A) All permutations
B) Odd permutations
C) Even permutations
D) Zero permutations
  • 93. What plays a role similar to addition in a ring for these matrix entries?
A) Identity morphisms
B) Coproducts
C) Tensor products
D) Initial objects
  • 94. What are the canonical morphisms from the coproduct of tensor products to the tensor product with a coproduct?
A) Zero morphisms
B) Isomorphisms
C) Epimorphisms
D) Monomorphisms
  • 95. What are the objects in the bicategory of C-matrices Mat(C)?
A) Vector spaces
B) Sets
C) Categories
D) Functors
  • 96. What is the identity 1-morphic matrix value when a equals b?
A) The initial object
B) The tensor unit I
C) The tensor product
D) The empty set
  • 97. What is the identity 1-morphic matrix value when a does not equal b?
A) The tensor unit I
B) A canonical isomorphism
C) The initial object
D) The identity set
  • 98. What is an example of an early encryption technique that used matrices?
A) The RSA algorithm
B) The Caesar cipher
C) The Enigma machine
D) The Hill cipher
  • 99. What method uses the overlap matrix and the Fock matrix to obtain molecular orbitals?
A) The Hill cipher method
B) The affine projection method
C) The Hartree–Fock method
D) The minimax method
  • 100. What equations are solved using the overlap matrix and Fock matrix in chemistry?
A) Game theory minimax equations
B) Linear programming equations
C) Complex number equations
D) The Roothaan equations
Created with That Quiz — a math test site for students of all grade levels.