Q. If a matrix is symmetric, what can be said about its elements? (2021)
A.
Aij = Aji
B.
Aij = -Aji
C.
Aij = 0
D.
Aij = Aii
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Solution
A symmetric matrix satisfies the condition Aij = Aji for all i and j.
Correct Answer:
A
— Aij = Aji
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Q. If a matrix is symmetric, what property does it have?
A.
A = A^T
B.
A = -A
C.
A^2 = I
D.
A = 0
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Solution
A symmetric matrix is defined by the property A = A^T, meaning it is equal to its transpose.
Correct Answer:
A
— A = A^T
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Q. If a matrix is symmetric, which of the following must be true? (2021)
A.
A = A^T
B.
A = -A^T
C.
A^2 = I
D.
A^T = 0
Show solution
Solution
A matrix A is symmetric if it is equal to its transpose, i.e., A = A^T.
Correct Answer:
A
— A = A^T
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Q. If a square has a perimeter of 32 cm, what is the length of one side? (2023)
A.
8 cm
B.
10 cm
C.
12 cm
D.
6 cm
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Solution
The perimeter P of a square is given by P = 4 * side. If P = 32 cm, then side = 32/4 = 8 cm.
Correct Answer:
A
— 8 cm
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Q. If B = [[1, 0, 2], [0, 1, 3], [0, 0, 1]], what is the rank of matrix B?
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Solution
The rank of matrix B is the number of non-zero rows in its row echelon form, which is 3.
Correct Answer:
C
— 3
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Q. If B = [[2, 3], [5, 7]], what is the value of det(B)? (2020)
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Solution
The determinant of B is calculated as (2*7) - (3*5) = 14 - 15 = -1.
Correct Answer:
A
— -1
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Q. If C = [[1, 0, 0], [0, 1, 0], [0, 0, 0]], what is the determinant of C? (2022)
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Solution
The determinant of C is 0 because it has a row of zeros.
Correct Answer:
B
— 0
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Q. If C = [[1, 0, 2], [-1, 3, 1], [2, 1, 0]], find det(C).
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Solution
Using the determinant formula for 3x3 matrices, det(C) = 1(3*0 - 1*1) - 0 + 2(-1*1 - 3*2) = 0 - 0 - 12 = -12.
Correct Answer:
A
— -9
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Q. If C = [[1, 0, 2], [0, 1, 3], [0, 0, 1]], what is det(C)? (2019)
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Solution
The determinant of an upper triangular matrix is the product of its diagonal elements. Here, det(C) = 1 * 1 * 1 = 1.
Correct Answer:
B
— 1
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Q. If C = [[1, 2], [3, 5]], find C^2.
A.
[[7, 14], [21, 35]]
B.
[[11, 28], [15, 35]]
C.
[[11, 16], [18, 35]]
D.
[[11, 16], [15, 25]]
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Solution
C^2 = C * C = [[1*1 + 2*3, 1*2 + 2*5], [3*1 + 5*3, 3*2 + 5*5]] = [[11, 16], [18, 35]].
Correct Answer:
C
— [[11, 16], [18, 35]]
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Q. If D = [[2, 1], [1, 2]], what is the trace of D?
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Solution
The trace of a matrix is the sum of its diagonal elements. Trace(D) = 2 + 2 = 4.
Correct Answer:
C
— 3
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Q. If D = [[4, 2], [1, 3]], find the inverse of D. (2022)
A.
[[3, -2], [-1, 4]]
B.
[[3, 2], [-1, 4]]
C.
[[3, -2], [1, 4]]
D.
[[4, -2], [-1, 3]]
Show solution
Solution
The inverse of D is given by (1/det(D)) * adj(D). Here, det(D) = (4*3) - (2*1) = 10, and adj(D) = [[3, -2], [-1, 4]]. Thus, D^(-1) = (1/10) * [[3, -2], [-1, 4]].
Correct Answer:
A
— [[3, -2], [-1, 4]]
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Q. If D = [[4, 2], [1, 3]], what is the inverse of D?
A.
[[3, -2], [-1, 4]]
B.
[[3, 2], [-1, 4]]
C.
[[4, -2], [-1, 3]]
D.
[[3, -4], [1, 2]]
Show solution
Solution
The inverse of D is given by (1/det(D)) * adj(D). Here, det(D) = (4*3) - (2*1) = 10. The adjugate is [[3, -2], [-1, 4]]. Thus, D^(-1) = (1/10) * [[3, -2], [-1, 4]].
Correct Answer:
A
— [[3, -2], [-1, 4]]
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Q. If E = [[1, 2], [2, 4]], what can be said about the matrix E? (2023)
A.
Invertible
B.
Singular
C.
Non-square
D.
Diagonal
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Solution
Matrix E is singular because its determinant is 0 (1*4 - 2*2 = 0).
Correct Answer:
B
— Singular
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Q. If F = [[1, 0], [0, 1]], what is F^(-1)?
A.
[[1, 0], [0, 1]]
B.
[[0, 1], [1, 0]]
C.
[[1, 1], [1, 1]]
D.
[[0, 0], [0, 0]]
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Solution
The inverse of the identity matrix F is itself, so F^(-1) = F.
Correct Answer:
A
— [[1, 0], [0, 1]]
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Q. If F = [[1, 2], [2, 4]], what is the determinant of F? (2021)
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Solution
The determinant of F is calculated as (1*4) - (2*2) = 4 - 4 = 0.
Correct Answer:
A
— 0
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Q. If F = [[1, 2], [2, 4]], what is the rank of F?
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Solution
The second row is a multiple of the first row, so there is only one linearly independent row. Therefore, the rank of F is 1.
Correct Answer:
A
— 1
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Q. If F = [[1, 2], [3, 5]], what is the trace of F? (2020)
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Solution
The trace of F is the sum of the diagonal elements: 1 + 5 = 6.
Correct Answer:
D
— 8
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Q. If G = [[2, 3], [5, 7]], find the eigenvalues of G.
A.
1, 8
B.
2, 7
C.
3, 5
D.
4, 6
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Solution
The eigenvalues are found by solving the characteristic equation det(G - λI) = 0. The eigenvalues are λ = 1, 8.
Correct Answer:
A
— 1, 8
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Q. If H = [[0, 1], [-1, 0]], what is the determinant of H? (2019)
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Solution
The determinant of H is calculated as (0*-0) - (1*-1) = 0 + 1 = 1.
Correct Answer:
C
— -1
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Q. If H = [[1, 2, 3], [0, 1, 4], [5, 6, 0]], find the determinant of H. (2022)
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Solution
Using the determinant formula for 3x3 matrices, det(H) = 1(1*0 - 4*6) - 2(0 - 4*5) + 3(0 - 1*5) = 0 - 40 - 15 = -55.
Correct Answer:
A
— -24
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Q. If H = [[1, 2], [2, 4]], what is the rank of H?
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Solution
The rank of H is 1 because the second row is a multiple of the first row.
Correct Answer:
A
— 1
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Q. If H = [[2, 3], [5, 7]], find the eigenvalues of H. (2023)
A.
1, 8
B.
2, 7
C.
3, 5
D.
4, 5
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Solution
The eigenvalues are found by solving the characteristic equation: det(H - λI) = 0, which gives λ^2 - 9λ + 1 = 0.
Correct Answer:
A
— 1, 8
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Q. If I = [[1, 1], [1, 1]], what is the rank of I? (2022)
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Solution
The rank of I is 1 because all rows are linearly dependent.
Correct Answer:
B
— 1
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Q. If I = [[1, 2, 3], [0, 1, 4], [5, 6, 0]], find the determinant of I.
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Solution
Using the determinant formula for 3x3 matrices, det(I) = 1(1*0 - 4*6) - 2(0 - 4*5) + 3(0 - 1*5) = 0 - 40 - 15 = -55.
Correct Answer:
A
— -24
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Q. If I = [[2, 1], [1, 2]], what is the trace of I?
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Solution
The trace of a matrix is the sum of its diagonal elements. Thus, trace(I) = 2 + 2 = 4.
Correct Answer:
C
— 3
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Q. If J = [[1, 1], [1, 1]], what is the rank of J?
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Solution
The rank of J is 1 because both rows are linearly dependent (they are identical).
Correct Answer:
B
— 1
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Q. If J = [[1, 2, 3], [4, 5, 6], [7, 8, 9]], what is det(J)?
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Solution
The determinant of J is 0, as the rows are linearly dependent.
Correct Answer:
A
— 0
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Q. If the diameter of a circle is 14 cm, what is its circumference? (2022)
A.
44 cm
B.
28 cm
C.
14 cm
D.
22 cm
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Solution
The circumference of a circle is given by C = πd, where d is the diameter. Here, C = π * 14 cm ≈ 44 cm.
Correct Answer:
A
— 44 cm
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Q. If the diameter of a sphere is 10 cm, what is its volume? (2023)
A.
100π cm³
B.
200π cm³
C.
300π cm³
D.
400π cm³
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Solution
The volume of a sphere is given by V = (4/3)πr³. The radius r = diameter/2 = 5 cm. Thus, V = (4/3)π(5)³ = (4/3)π(125) = 500/3 π cm³.
Correct Answer:
B
— 200π cm³
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