PYQSidePowered byPrepblink ExamsMy practice

Determinants

JEE Main 2024 (Online) 30th January Morning ShiftMCQMedium📈 Topic in 59% papers+4−1
Ques. 1JEE Main 2024, 30 January (Morning Shift)

Consider the system of linear equations x+y+z=4 , x+2y+2 z=10 , x+3y+4 2z= 2+15 where , . Which one of the following statements is NOT correct ?

  1. The system has unique solution if 12 and 1, 15
  2. The system has infinite number of solutions if = 12 and =15
  3. The system is consistent if 12
  4. The system is inconsistent if = 12 and 1

Answer

(4) The system is inconsistent if = 12 and 1

Solution

= vmatrix1&1&1\\1&2&2 \\1&3&4 2 vmatrix=4 2-4 +1=(2 -1)2

12 0 unique solution (for every ) ⇒ (A), (C) are correct

= 12: x+y+z=4 , x+2y+z=10 , x+3y+z= 2+15

Subtracting successive equations: y=6 and y= 2-10 +15

2-16 +15=0 =1 or 15 (infinite solutions) ⇒ (B) is correct

(D): = 12, =15 ( 1) gives infinite solutions, not inconsistent ⇒ (D) is NOT correct

Answer: (4)

Keep practising — Determinants

Ques. 2JEE Main 2024, 30 January (Evening Shift)

Let R= pmatrixx&0&0\\0&y&0\\0&0&z pmatrix be a non-zero 3 3 matrix, where x =y ( + 2 3 )=z ( + 4 3 ) 0, (0,2 ). For a square matrix M, let trace (M) denote the sum of all the diagonal entries of M. Then, among the statements: (I) Trace (R)=0 (II) If trace (adj(adj(R)))=0, then R has exactly one non-zero entry.

  1. Only (I) is true
  2. Only (II) is true
  3. Both (I) and (II) are true
  4. Neither (I) nor (II) is true
Ques. 3JEE Main 2024, 30 January (Evening Shift)

Consider the system of linear equations x+y+z=5, x+2y+ 2 z=9, x+3y+ z= , where , R. Then, which of the following statements is NOT correct?

  1. System is consistent if 1 and =13
  2. System is inconsistent if =1 and 13
  3. System has unique solution if 1 and 13
  4. System has infinite number of solutions if =1 and =13
Ques. 4JEE Main 2024, 29 January (Morning Shift)

Let A= bmatrix1&0&0\\0& & \\0& & bmatrix and |2A|3=221 where , Z. Then a value of is

  1. 9
  2. 17
  3. 3
  4. 5
Ques. 5JEE Main 2024, 29 January (Evening Shift)

Let A= bmatrix2&1&2\\6&2&11\\3&3&2 bmatrix and P= bmatrix1&2&0\\5&0&2\\7&1&5 bmatrix. The sum of the prime factors of |P-1AP-2I | is equal to

  1. 66
  2. 27
  3. 23
  4. 26
Ques. 6JEE Main 2024, 29 January (Evening Shift)

Let for any three distinct consecutive terms a, b, c of an A.P, the lines ax+by+c=0 be concurrent at the point P and Q( , ) be a point such that the system of equations x+y+z=6, 2x+5y+ z= and x+2y+3z=4, has infinitely many solutions. Then (PQ)2 is equal to .

Ques. 7JEE Main 2024, 27 January (Morning Shift)

Let A= bmatrix2&0&1\\1&1&0\\1&0&1 bmatrix, B= [B1, B2, B3 ], where B1, B2, B3 are column matrices, and AB1= bmatrix1\\0\\0 bmatrix, AB2= bmatrix2\\3\\0 bmatrix, AB3= bmatrix3\\2\\1 bmatrix If =|B| and is the sum of all the diagonal elements of B, then 3+ 3 is equal to .

Ques. 8JEE Main 2024, 27 January (Evening Shift)

The values of , for which vmatrix1 & 32 & + 32\ 1 & 13 & + 13\ 2 +3 & 3 +1 & 0 vmatrix=0, lie in the interval

  1. (-2,1)
  2. (- 32, 32 )
  3. (-3,0)
  4. (0,3)

All Determinants PYQs →

PDFDownload Determinants PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Main Mathematics chapters