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Determinants

JEE Main 2024 (Online) 5th April Morning ShiftMCQMedium📈 Topic in 38% papers+4−1
Ques. 1JEE Main 2024, 5 April (Morning Shift)

Let A and B be two square matrices of order 3 such that |A| = 3 and |B| = 2. Then |ATA(adj(2 A))-1(adj(4 B))(adj(AB))-1AAT| is equal to :

  1. 32
  2. 81
  3. 64
  4. 108

Answer

(3) 64

Solution

For order 3: |kM| = k3|M|, |adj M| = |M|2, | M-1| = 1|M|

|adj(2A)| = (8 3)2 = 576, |adj(4B)| = (64 2)2 = 16384, |adj(AB)| = 62 = 36

∵ |ATA| = |AAT| = 3 3 = 9

Required value = 9 1576 16384 136 9

= 81 1638420736 = 64

Answer: (3)

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Ques. 2JEE Main 2024, 5 April (Morning Shift)

If the system of equations 11x + y + z = -5 2x + 3y + 5z = 3 8x - 19y - 39z = has infinitely many solutions, then 4 - is equal to :

  1. 51
  2. 45
  3. 47
  4. 49
Ques. 3JEE Main 2024, 5 April (Evening Shift)

The values of m, n, for which the system of equations x + y + z = 4, 2x + 5y + 5z = 17, x + 2y + mz = n has infinitely many solutions, satisfy the equation :

  1. m2 + n2 - m - n = 46
  2. m2 + n2 + mn = 68
  3. m2 + n2 - mn = 39
  4. m2 + n2 + m + n = 64
Ques. 4JEE Main 2024, 5 April (Evening Shift)

Let 0 and A = bmatrix & & 3 \ & & \ - & & 2 bmatrix. If B = bmatrix 3 & -9 & 3 \ - & 7 & -2 \ -2 & 5 & -2 bmatrix is the matrix of cofactors of the elements of A, then (AB) is equal to :

  1. 64
  2. 343
  3. 125
  4. 216
Ques. 5JEE Main 2024, 4 April (Morning Shift)

Let (0, ) and A= bmatrix1 & 2 & \ 1 & 0 & 1 \ 0 & 1 & 2 bmatrix. If det ( adj (2A-AT ) adj (A-2AT ) )=28, then ( det(A))2 is equal to:

  1. 16
  2. 36
  3. 49
  4. 1
Ques. 6JEE Main 2024, 4 April (Morning Shift)

If the system of equations x+( 2 )y+( 2 )z=0 x+( )y+( )z=0 x+( )y-( )z=0 has a non-trivial solution, then (0, 2 ) is equal to :

  1. 5 24
  2. 11 24
  3. 7 24
  4. 3 4
Ques. 7JEE Main 2024, 4 April (Morning Shift)

Let A be a 3 3 matrix of non-negative real elements such that A bmatrix1\\1\\1 bmatrix=3 bmatrix1\\1\\1 bmatrix. Then the maximum value of (A) is .

Ques. 8JEE Main 2024, 1 February (Morning Shift)

If A= bmatrix 2 & 1\ -1 & 2 bmatrix, B= bmatrix1 & 0\ 1 & 1 bmatrix, C=ABAT and X=ATC2A, then is equal to :

  1. 243
  2. 729
  3. 27
  4. 891
Ques. 9JEE Main 2024, 1 February (Morning Shift)

If the system of equations 2x+3y-z=5 x+ y+3z=-4 3x-y+ z=7 has infinitely many solutions, then 13 is equal to :

  1. 1110
  2. 1120
  3. 1210
  4. 1220
Ques. 10JEE Main 2024, 1 February (Evening Shift)

Let the system of equations x+2 y+3 z=5, 2 x+3 y+z=9, 4 x+3 y+ z= have infinite number of solutions. Then +2 is equal to :

  1. 22
  2. 17
  3. 15
  4. 28
Ques. 11JEE Main 2024, 31 January (Morning Shift)

If the system of linear equations x-2y+z=-4 2x+ y+3z=5 3x-y+ z=3 has infinitely many solutions, then 12 +13 is equal to

  1. 60
  2. 54
  3. 64
  4. 58

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