Home
Class 11
MATHS
If A = |(a,b,c),(x,y,z),(p,q,r)| and B =...

If `A = |(a,b,c),(x,y,z),(p,q,r)| and B = |(q,-b,y),(-p,a,-x),(r,-c,z)|`, then

A

`A = 2B`

B

`A = B`

C

`A = -B`

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the determinants \( A \) and \( B \) given in the question. We will manipulate the determinants step by step to find a relationship between them. Given: \[ A = \begin{vmatrix} a & b & c \\ x & y & z \\ p & q & r \end{vmatrix} \] \[ B = \begin{vmatrix} q & -b & y \\ -p & a & -x \\ r & -c & z \end{vmatrix} \] ### Step 1: Interchange Columns We can interchange columns in the determinant \( B \). Let's interchange column 1 and column 2. When we interchange two columns, we introduce a negative sign: \[ B = -\begin{vmatrix} -b & q & y \\ a & -p & -x \\ -c & r & z \end{vmatrix} \] **Hint:** Remember that interchanging two columns in a determinant changes the sign of the determinant. ### Step 2: Interchange Rows Next, we can interchange row 1 and row 2 in the determinant we obtained from the previous step. This will again introduce a negative sign: \[ B = -\begin{vmatrix} a & -p & -x \\ -b & q & y \\ -c & r & z \end{vmatrix} \] \[ B = -(-1)\begin{vmatrix} -b & q & y \\ a & -p & -x \\ -c & r & z \end{vmatrix} = \begin{vmatrix} -b & q & y \\ a & -p & -x \\ -c & r & z \end{vmatrix} \] **Hint:** Interchanging rows also changes the sign of the determinant. ### Step 3: Factor Out Constants Now, we can factor out the negative signs from the first column and the second row: \[ B = (-1)(-1)\begin{vmatrix} b & q & y \\ a & p & x \\ c & r & z \end{vmatrix} = \begin{vmatrix} b & q & y \\ a & p & x \\ c & r & z \end{vmatrix} \] **Hint:** When you factor out a negative sign from a column or row, it changes the sign of the determinant. ### Step 4: Rearranging the Determinant Now we can rearrange the determinant \( B \) to match the structure of \( A \): \[ B = \begin{vmatrix} a & b & c \\ x & y & z \\ p & q & r \end{vmatrix} = A \] ### Step 5: Final Relationship Thus, we find that: \[ B = -A \] ### Conclusion The relationship between the determinants is: \[ \text{det}(B) = -\text{det}(A) \] The correct option is that \( B \) is equal to the negative of \( A \).
Promotional Banner

Topper's Solved these Questions

  • DETERMINANTS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|92 Videos
  • CARTESIAN CO-ORDINATE SYSTEM

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|27 Videos
  • DISCRETE PROBABILITY DISTRIBUTIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|40 Videos

Similar Questions

Explore conceptually related problems

If A=[(a,b,c),(x,y,z),(p,q,r)], B=[(q,-b,y),(-p,a,-x),(r,-c,z)] and If A is invertible, then which of the following is not true ?

If A=[(a, b, c), (x, y, z), (p, q, r)], B=[(q,-b, y),(-p, a,-x),(r,-c, z)] and if A is invertible, then which of the following is not true? (a) |A|=|B| (b) |A|=-|B| (c) |adj A|=|adj B| (d) A is invertible if and only if B is invertible

If A=|[a, b, c],[ x, y, z],[ p, q, r]| and B=|[q, -b, y],[ -p, a, -x],[ r,-c, z]| , without expanding or evaluating A and B , show that A+B=0 .

If A = [[a,b,c],[x,y,z],[p,q,r]], B= [[q , -b,y],[-p,a,-x],[r,-c,z]] and if A is invertible, then which of the following is not true?

If Delta_1=|[a, b, c],[ x, y, z],[ p, q, r]| and Delta_2=|[q,-b, y],[-p, a,-x],[ r,-c, z]|, without expanding or evaluating Delta_1 and Delta_2 , show that Delta_1+Delta_2=0

If |{:(a-b,b-c,c-a),(x-y,y-z,z-x),(p-q,q-r,r-p):}|=m|{:(c,a,b),(z,x,y),(r,p,q):}|," then m"=

Prove that: |{:(a, b, c), (x, y, z), (p, q, r):}|=|{:(y, b, q), (x, a, p), (z, c, r):}|

If P=[(x,0, 0),( 0,y,0 ),(0, 0,z)] and Q=[(a,0 ,0 ),(0,b,0 ),(0, 0,c)] , prove that P Q=[(x a,0 ,0 ),(0,y b,0),( 0 ,0,z c)]=Q P

Delta=|{:(p,q,r),(p+2a,q+2b,r+2c),(a,b,c):}| then

Without, prove that : |{:(1+b,b+c,c+a),(p+q,q+r,r+p),(x+y,y+z,z+x),:}|=2|{:(a,b,c),(p,q,r),(x,y,z):}|

OBJECTIVE RD SHARMA ENGLISH-DETERMINANTS-Chapter Test
  1. If x, y , z are in A.P., then the value of the det (A) is , where A ...

    Text Solution

    |

  2. The value of |(b +c,a,a),(b,c +a,b),(c,c,a +b)|, is

    Text Solution

    |

  3. If a ,\ b ,\ c are non-zero real numbers and if the system of equat...

    Text Solution

    |

  4. If a!=6,b,c satisfy|[a,2b,2c],[3,b,c],[4,a,b]|=0 ,then abc =

    Text Solution

    |

  5. The value of Delta = |(1^(2),2^(2),3^(2)),(2^(2),3^(2),4^(2)),(3^(2),4...

    Text Solution

    |

  6. Prove: |a a+b a+2b a+2b a a+b a+b a+2b a|=9(a+b)b^2

    Text Solution

    |

  7. If all the elements in a square matrix A of order 3 are equal to 1 or ...

    Text Solution

    |

  8. Sum of real roots of the euation |{:(1,4,20),(1,-2,5),(1,2x,5x^(2)):}|...

    Text Solution

    |

  9. If f(x)=|{:(sinx,cosx,tanx),(x^(3),x^(2),x),(2x,1,x):}|, then lim(xto0...

    Text Solution

    |

  10. If A, B and C are the angles of a triangle and |(1,1,1),(1 + sin A,1...

    Text Solution

    |

  11. If |(x,2,3),(2,3,x),(3,x,2)|=|(1,x,4),(x,4,1),(4,1,x)|=|(0,5,x),(5,x,0...

    Text Solution

    |

  12. Using properties of determinants, solve for x:|a+x a-x a-x a-x a+x a...

    Text Solution

    |

  13. If Delta(1) = |(7,x,2),(-5,x +1,3),(4,x,7)| and Delta(2) = |(x,2,7),(x...

    Text Solution

    |

  14. If Delta1=|{:(10,4,3),(17,7,4),(4,-5,7):}|,Delta2=|{:(4,x+5,3),(7,x+12...

    Text Solution

    |

  15. If |(a,a +d,a +2d),(a^(2),(a + d)^(2),(a + 2d)^(2)),(2a + 3d,2 (a +d),...

    Text Solution

    |

  16. If Delta(k) = |(k,1,5),(k^(2),2n +1,2n +1),(k^(3),3n^(2),3n +1)|, " th...

    Text Solution

    |

  17. If the system of equations bx + ay = c, cx + az = b, cy + bz = a h...

    Text Solution

    |

  18. If a,b,c are non-zeros, then the system of equations {:((alpha+a)x+a...

    Text Solution

    |

  19. If p^(th), q^(th),r^(th) terms an A.P are 1/a,1/b and 1/c respectively...

    Text Solution

    |

  20. If A = |(a,b,c),(x,y,z),(p,q,r)| and B = |(q,-b,y),(-p,a,-x),(r,-c,z)|...

    Text Solution

    |