JEE Mathematics Matrices MCQs Set A

Question:

• a) none of these
• b) xyz . pqr/abc
• c) pqr abc/xyz
• d) pqr . abc/xyz

Answer: none of these

Question: If X and Y are matrices satisfying X + Y = I and 2X – 2Y = I where I is the unit matrix of order 3, then X equals:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) –3, –2, 4, 5
• b) 3, –4, 2, –3
• c) 4, 2, 3, –3
• d) –4, 2, 3, –3

Answer: –3, –2, 4, 5

Question:

• a) – I
• b) I
• c) – A
• d) A

Answer: – I

Question: If A, B, C are square matrices of the same order, then which of the following is true?

• a)

  

• b) (AB)² = A²B²
• c)

  

• d) AB = AC

Answer:

Question: The matrix [a₁x₁ + a₂x₂ + a₃x₃] is of order :

• a) 1 × 1
• b) 1 × 2
• c) 1 × 3
• d) 2 × 1

Answer: 1 × 1

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  AB ≠ BA

• b) AB = BA
• c) B² = B
• d) A²= A

Answer: AB ≠ BA

Question:

• a) (2, 3, 4)
• b) (4, 3, 2)
• c) (3, 2, 4)
• d) none

Answer: (2, 3, 4)

More Questions..............................

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) 2
• b) 7
• c) 3
• d) 5

Answer: 2

Question:

A² = B² = C² is equal to :

• a) – I
• b) I²
• c)  I
• d) 2I

Answer: – I

Question:

• a) 16A
• b) 5A
• c) 10A
• d) 32A

Answer: 16A

Question: Assuming that the sums and products given below are defined which of the following is not true for matrices?

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: The inverse of a symmetric matrix is

• a) a symmetric matrix
• b) square matrix
• c) skew symmetric matrix
• d) diagonal matrix

Answer: a symmetric matrix

Question:

• a)

  

• b)

  

• c)

  

• d) none of these

Answer:

Question: If A = [a_ij] is a skew-symmetric matrix of order n, then a_ij is equal to:

• a) 0 for all i = 1, 2, ...n
• b) 1 for all i = 1, 2,..., n
• c) 0 for some i
• d) 1 for some i

Answer: 0 for all i = 1, 2, ...n

Question: If | A | = 2 and A is a 2 × 2 matrix, then the value of det. {adj. {adj. (adj. A2)}} is equal to:

• a) 4
• b) 64
• c) 16
• d) 128

Answer: 4

Question: If A is an invertible matrix and B is a matrix, then:

• a) rank (AB) = rank (B)
• b) rank (AB) > rank (A)
• c) rank (AB) = rank (A)
• d) rank (AB) > rank (B)

Answer: rank (AB) = rank (B)

Question: If A and B are Hermition matrices of the same order, then (AB – BA) is:

• a) a Skew-Hermition matrix
• b) a null matrix
• c) a Hermition matrix
• d) none of these

Answer: a Skew-Hermition matrix

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) y = 1
• b) x + y = 1
• c) x = 1
• d) x = y

Answer: y = 1

Question: Let A and B be two matrices then (AB)' equals:

• a) B'A'
• b) – AB
• c) A'B
• d) 1

Answer: B'A'

Question:

• a) multiplied by 4
• b) not changed
• c) doubled
• d) multiplied by 8

Answer: multiplied by 4

Question:

• a) exists and equals A²
• b) none of these
• c) exists and equals I – A
• d) exists and equals I + A

Answer: exists and equals A²

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: If A is n × n matrix, then adj (adj A) =

• a) | A |^n–2 A
• b) | A |^n–1 A
• c)  none
• d) | A |ⁿ A

Answer: | A |^n–2 A

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer: