Home
Class 12
MATHS
If Delta = |{:(1,2,3),(2,3,5),(3,6,12):}...

If `Delta = |{:(1,2,3),(2,3,5),(3,6,12):}|and Delta' = |{:(4,8,15),(3,6,12),(2,3,5):}|` , then

A

`Delta' = 2 Delta`

B

`Delta' = - 2 Delta`

C

`Delta' = Delta`

D

`Delta' = - Delta`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to calculate the values of the determinants \( \Delta \) and \( \Delta' \) and then find the relationship between them. ### Step 1: Calculate \( \Delta \) Given: \[ \Delta = \begin{vmatrix} 1 & 2 & 3 \\ 2 & 3 & 5 \\ 3 & 6 & 12 \end{vmatrix} \] We will expand this determinant using the first row. \[ \Delta = 1 \cdot \begin{vmatrix} 3 & 5 \\ 6 & 12 \end{vmatrix} - 2 \cdot \begin{vmatrix} 2 & 5 \\ 3 & 12 \end{vmatrix} + 3 \cdot \begin{vmatrix} 2 & 3 \\ 3 & 6 \end{vmatrix} \] ### Step 2: Calculate the 2x2 determinants 1. For \( \begin{vmatrix} 3 & 5 \\ 6 & 12 \end{vmatrix} \): \[ = (3 \cdot 12) - (5 \cdot 6) = 36 - 30 = 6 \] 2. For \( \begin{vmatrix} 2 & 5 \\ 3 & 12 \end{vmatrix} \): \[ = (2 \cdot 12) - (5 \cdot 3) = 24 - 15 = 9 \] 3. For \( \begin{vmatrix} 2 & 3 \\ 3 & 6 \end{vmatrix} \): \[ = (2 \cdot 6) - (3 \cdot 3) = 12 - 9 = 3 \] ### Step 3: Substitute back into the determinant calculation Now substituting these values back into the equation for \( \Delta \): \[ \Delta = 1 \cdot 6 - 2 \cdot 9 + 3 \cdot 3 \] \[ = 6 - 18 + 9 \] \[ = 6 - 18 + 9 = -3 \] ### Step 4: Calculate \( \Delta' \) Now we calculate \( \Delta' \): Given: \[ \Delta' = \begin{vmatrix} 4 & 8 & 15 \\ 3 & 6 & 12 \\ 2 & 3 & 5 \end{vmatrix} \] We will expand this determinant using the first row. \[ \Delta' = 4 \cdot \begin{vmatrix} 6 & 12 \\ 3 & 5 \end{vmatrix} - 8 \cdot \begin{vmatrix} 3 & 12 \\ 2 & 5 \end{vmatrix} + 15 \cdot \begin{vmatrix} 3 & 6 \\ 2 & 3 \end{vmatrix} \] ### Step 5: Calculate the 2x2 determinants for \( \Delta' \) 1. For \( \begin{vmatrix} 6 & 12 \\ 3 & 5 \end{vmatrix} \): \[ = (6 \cdot 5) - (12 \cdot 3) = 30 - 36 = -6 \] 2. For \( \begin{vmatrix} 3 & 12 \\ 2 & 5 \end{vmatrix} \): \[ = (3 \cdot 5) - (12 \cdot 2) = 15 - 24 = -9 \] 3. For \( \begin{vmatrix} 3 & 6 \\ 2 & 3 \end{vmatrix} \): \[ = (3 \cdot 3) - (6 \cdot 2) = 9 - 12 = -3 \] ### Step 6: Substitute back into the determinant calculation for \( \Delta' \) Now substituting these values back into the equation for \( \Delta' \): \[ \Delta' = 4 \cdot (-6) - 8 \cdot (-9) + 15 \cdot (-3) \] \[ = -24 + 72 - 45 \] \[ = -24 + 72 - 45 = 3 \] ### Step 7: Find the relationship between \( \Delta \) and \( \Delta' \) We have: \[ \Delta = -3 \quad \text{and} \quad \Delta' = 3 \] Thus, we can see that: \[ \Delta = -\Delta' \] ### Final Answer The relationship is: \[ \Delta = -\Delta' \]
Promotional Banner

Topper's Solved these Questions

  • DETERMINANTS

    DISHA PUBLICATION|Exercise EXERCISE -2 CONCEPT APPLICATOR|30 Videos
  • DETERMINANTS

    DISHA PUBLICATION|Exercise EXERCISE -2 CONCEPT APPLICATOR|30 Videos
  • CONTINUITY AND DIFFERENTIABILITY

    DISHA PUBLICATION|Exercise Exercise-2 : Concept Applicator|30 Videos
  • DIFFERENTIAL EQUATIONS

    DISHA PUBLICATION|Exercise Exercise-2 : Concept Applicator|30 Videos

Similar Questions

Explore conceptually related problems

If A{:[(1,2,3,5,6),(4,-1,2,-3,1)]:}andB={:[(5,3),(2,1),(-3,5),(4,1),(1,2)]:} , then find AB and BA.

Evaluate Delta = |{:(3, 4, 5), (-6, 2, -3), (8, 1, 7):}|

If A({:(1,3,4),(3,-1,5),(-2,4,-3):})=({:(3,-1,5),(1,3,4),(+4,-8,6):}) , then A=

if A=[{:(1,2,-5),(-3,4,6):}]and B[{:(-2,3,-4),(1,2,3):}]' then find 2A+B.

If A={:[(2,3,5,6),(-1,2,-3,4)]:}andB={:[(4,-5,3,7),(8,-3,-1,2)]:} , then find A^(T)+B^(T)and(A+B)^(T) . What do you notice ?

Delta=|[5,3,8],[2,0,1],[1,2,3]|=

If ,A = [(1,2),(-2,4)] ,then -3A= [(-3,-6),(6,-12)]

If Delta = |(5,3,8),(6,0,4),(1,2,3)| then the minor of the element a_(21) is

Find the inverses of the following matrices by adjoint method : (1) {:((1,2),(2,3)):}" "(2){:((5,4),(3,2)):}" "(3){:((3,-2),(6,8)):}" "(4){:((2,-3),(3,5)):} .

DISHA PUBLICATION-DETERMINANTS-EXERCISE -1 CONCEPT BUILDER
  1. If A [{:(1,2),(3,5):}] , then the value of the determinant | A^(2009) ...

    Text Solution

    |

  2. Prove that the determinant Delta =|{:(x,,sin0,,cos 0),(-sin 0,,-x,...

    Text Solution

    |

  3. If Delta = |{:(1,2,3),(2,3,5),(3,6,12):}|and Delta' = |{:(4,8,15),(3,6...

    Text Solution

    |

  4. If C(ij) is the cofactor of the element a(ij) of the determinant |{:(2...

    Text Solution

    |

  5. The parameter on which the value of the determinant |1a a^2"cos"(p-d)x...

    Text Solution

    |

  6. If a != b != c, are value of x which satisfies the equation |(0,x -a...

    Text Solution

    |

  7. If |{:(x^(2) +x , 3x - 1 , -x + 3),(2x +1 , 2 + x^(2) , x^(3) - 3),(x ...

    Text Solution

    |

  8. Matrix M(r) is defined as M(r) = ({:(r,r-1),(r-1,r):}), r in N. The v...

    Text Solution

    |

  9. If a, b, c are complex numbers, then the determinant Delta = |(0,-b,...

    Text Solution

    |

  10. If in a triangle ABC, |{:(1, sin A ,sin^(2)A),(1,sin B , sin^(2)B),(1,...

    Text Solution

    |

  11. The value of |(.^(10)C(4).^(10)C(5).^(11)C(m)),(.^(11)C(6).^(11)C(7).^...

    Text Solution

    |

  12. If f(x) = |{:(cos^(2)x, cosx.sinx, -sin x),(cos x sinx ,sin^(2)x ,cos ...

    Text Solution

    |

  13. If plambda^(4) + q lambda^(3) + r lambda^(2) + s lambda + t = |{:(b^(...

    Text Solution

    |

  14. If a,b,c are in A.P then the value of |[x+1, x+2, x+a] , [x+2, x+3, x+...

    Text Solution

    |

  15. |[sin^2(13^@),sin^2(77^@),tan135^@],[sin^2(77^@),tan135^@,sin^2(13^@)]...

    Text Solution

    |

  16. The roots of the equations |{:(1+x,3,5),(2,2+x,5),(2,3,x+4):}| = 0 are

    Text Solution

    |

  17. The value of the determinant |((a^x+a^-x)^2, (a^x-a^-x)^2, 1),(b^x+b^-...

    Text Solution

    |

  18. If a, b, c, are in A.P, find value of |a y+4 5y+7 8y+a3y+5 6y+8 9y+b4...

    Text Solution

    |

  19. suppose D= |{:(a(1),,b(1),,c(1)),(a(2),,b(2),,c(2)),(a(3),,b(3),,c(3...

    Text Solution

    |

  20. If D =|{:(1,1,1),(1,1+x,1),(1,1,1+y):}|"for" " "xne0,yne0 then D is

    Text Solution

    |