Home
Class 12
MATHS
If a,b,c be all distinct and |(a^3-1,b...

If a,b,c be all distinct and
`|(a^3-1,b^3-1,c^3-1),(a,b,c),(a^2,b^2,c^2)|=0` then

A

`sum ab = 0 `

B

`sum a = 0`

C

`abc = 1`

D

`sum a = 1`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the determinant given by: \[ D = \begin{vmatrix} a^3 - 1 & b^3 - 1 & c^3 - 1 \\ a & b & c \\ a^2 & b^2 & c^2 \end{vmatrix} \] and we know that \(D = 0\). ### Step 1: Factor the first row The first row can be factored as follows: \[ a^3 - 1 = (a - 1)(a^2 + a + 1) \] \[ b^3 - 1 = (b - 1)(b^2 + b + 1) \] \[ c^3 - 1 = (c - 1)(c^2 + c + 1) \] Thus, we can rewrite the determinant as: \[ D = \begin{vmatrix} (a - 1)(a^2 + a + 1) & (b - 1)(b^2 + b + 1) & (c - 1)(c^2 + c + 1) \\ a & b & c \\ a^2 & b^2 & c^2 \end{vmatrix} \] ### Step 2: Factor out the common terms We can factor out \((a - 1)\), \((b - 1)\), and \((c - 1)\) from the first row: \[ D = (a - 1)(b - 1)(c - 1) \begin{vmatrix} a^2 + a + 1 & b^2 + b + 1 & c^2 + c + 1 \\ a & b & c \\ a^2 & b^2 & c^2 \end{vmatrix} \] ### Step 3: Analyze the determinant Now we have: \[ D = (a - 1)(b - 1)(c - 1) \cdot D' \] where \[ D' = \begin{vmatrix} a^2 + a + 1 & b^2 + b + 1 & c^2 + c + 1 \\ a & b & c \\ a^2 & b^2 & c^2 \end{vmatrix} \] ### Step 4: Set the determinant to zero Since \(D = 0\), we have two cases to consider: 1. \( (a - 1)(b - 1)(c - 1) = 0 \) 2. \( D' = 0 \) ### Step 5: Solve for distinct values From the first case, we have: - \( a = 1 \) - \( b = 1 \) - \( c = 1 \) However, \(a\), \(b\), and \(c\) are distinct, so this case does not yield valid solutions. ### Step 6: Analyze the second determinant Now we need to analyze \(D'\): \[ D' = \begin{vmatrix} a^2 + a + 1 & b^2 + b + 1 & c^2 + c + 1 \\ a & b & c \\ a^2 & b^2 & c^2 \end{vmatrix} \] To evaluate \(D'\), we can use properties of determinants or perform row operations. The determinant will be zero if the rows are linearly dependent. ### Step 7: Conclusion The determinant \(D' = 0\) implies that the rows are linearly dependent, which can happen if: \[ a + b + c = 0 \quad \text{or} \quad ab + bc + ca = 0 \quad \text{or} \quad abc = 1 \] Thus, we conclude that the condition \(D = 0\) leads to the relationships among \(a\), \(b\), and \(c\) as stated.
Promotional Banner

Topper's Solved these Questions

  • DETERMINANTS

    ML KHANNA|Exercise Problem Set (2) (TRUE AND FALSE) |3 Videos
  • DETERMINANTS

    ML KHANNA|Exercise Problem Set (2) (FILL IN THE BLANKS) |1 Videos
  • DETERMINANTS

    ML KHANNA|Exercise Problem Set (1) (TRUE AND FALSE) |7 Videos
  • DEFINITE INTEGRAL

    ML KHANNA|Exercise Miscellaneous Questions (Assertion/Reason)|1 Videos
  • DIFFERENTIAL EQUATIONS

    ML KHANNA|Exercise MISCELLANEOUS EXERCISE (Matching Entries) |2 Videos

Similar Questions

Explore conceptually related problems

If a!=b!=c such that |[a^3-1,b^3-1,c^3-1] , [a,b,c] , [a^2,b^2,c^2]|=0 then

If a,b,c are all distinct and |[a,a^3,a^4-1],[b,b^3,b^4-1],[c,c^3,c^4-1]| =0, show that abc(ab+bc+ac) = a+b+c

Suppose a,b,c, gt0 and |(a^(3)-1,a^(2),a),(b^(3)-1,b^(2),b),(c^(3)-1,c^(2),c)|=0 then least possible value of a+b+c is ____________

If A=|(1,1,1),(a,b,c),(a^3,b^3,c^3)|, B=|(1,1,1),(a^2,b^2,c^2),(a^3,b^3,c^3)|, C=|(a,b,c),(a^2,b^2,c^2),(a^3,b^3,c^3)| , then which relation is correct :

If a,b, and c are all different and if |{:(a,a^(2),1+a^(3)),(b,b^(2),1+b^(3)),(c,c^(2),1+c^(3)):}| =0 Prove that abc =-1.

Three linear equations a_1x+b_1y+c_1z=0, a_2x+b_2y+c_2z=0,a_3x+b_3y+c_3z=0 are consistent if (A) |(a_1,b_1,c_1),(a_2,b_2,c_2),(a_3,b_3,c_3)|=0 (B) |(a_1,b_1,c_1),(a_2,b_2,c_2),(a_3,b_3,c_3)|=-1 (C) a_1b_1c_1+a_2b_2c_2+a_3b_3c_3=0 (D) none of these

|[a,a^2,a^3-1],[b,b^2,b^3-1],[c,c^2,c^3-1]|=0 prove that abc= I

The value of the determinant |(1,a,a^2-bc),(1,b,b^2-ca),(1,c,c^2-ab)| is (A) (a+b+c),(a^2+b^2+c^2) (B) a^3+b^3+c^3-3abc (C) (a-b)(b-c)(c-a) (D) 0

If delta =|(a_1,b_1,c_1),(a_2,b_2,c_2),(a_3,b_3,c_3)| then the value of |(2a_1+3b_1+4c_1,b_1,c_1),(2a2+3b_2+4c_2,b_2,c_2),(2a_3+3b_3+4c_3,b_3,c_3)| is equal to

ML KHANNA-DETERMINANTS -Problem Set (2) (MULTIPLE CHOICE QUESTIONS)
  1. If R be the circum radius of the triangle ABC then the value of R^3...

    Text Solution

    |

  2. If a, b, c are sides of a triangle and |(a^2,b^2,c^2),((a+1)^2,(b+1...

    Text Solution

    |

  3. If A+B+C=pi, show that |(sin^2A,sinAcosA,cos^2A),(sin^2B,sinBcosB,cos...

    Text Solution

    |

  4. If x,y,z are all distinct and |(x,x^2,1+x^3),(y,y^2,1+y^3),(z,z^2,1...

    Text Solution

    |

  5. If |(x+a,a^2,a^3),(x+b,b^2,b^3),(x+c,c^2,c^3)| = 0 , a ne b ne c then ...

    Text Solution

    |

  6. If a,b,c be all distinct and |(a^3-1,b^3-1,c^3-1),(a,b,c),(a^2,b^2,c...

    Text Solution

    |

  7. If a,b,c are different , then the determinant |(1,1,1),((x-a)^2,(x-b...

    Text Solution

    |

  8. If |(x^(lamda),x^(lamda+2),x^(lamda+3)),(y^(lamda),y^(lamda+2),y^(lamd...

    Text Solution

    |

  9. Prove that |{:(x^(2),,x^(2)-(y-z)^(2),,yz),(y^(2),,y^(2)-(z-x)^(2),,zx...

    Text Solution

    |

  10. If a,b,c are negative distinct real numbers then the determinant |(a,b...

    Text Solution

    |

  11. the value of the determinant |(b+c,a-b,a),(c+a,b-c,b),(a+b,c-a,c)| is

    Text Solution

    |

  12. If |(x,y,z),(y,z,x),(z,x,y)|=-(x+y+z)(x+yk+zk^2)(x+yk^2+zk) then k eq...

    Text Solution

    |

  13. If a,b,c are the roots of x^3+px^2+q=0 , then the value of |(a,b,c),(b...

    Text Solution

    |

  14. If a,b,c are non-zero real number such that |(bc,ca,ab),(ca,ab,bc),(ab...

    Text Solution

    |

  15. If both n and r be greater than 1 and if Delta=|(""^xCr,""^(n-1)Cr,"...

    Text Solution

    |

  16. If Delta=|(""^(10)C3,""^(10)C4,""^(11)Cn),(""^(11)C5,""^(11)C6,""^(12)...

    Text Solution

    |

  17. If Delta = |(""^(5)C0,""^(5)C3,14),(""^(5)C1,""^(5)C4,1),(""^(5)C2,""^...

    Text Solution

    |

  18. The value of the determinant |(1,1,1),(.^(m)C(1),.^(m +1)C(1),.^(m+2)C...

    Text Solution

    |

  19. The determinant |(y^(2),-xy,x^(2)),(a,b,c),(a',b',c')| is equal to

    Text Solution

    |

  20. |(bc,bc'+b'c,b'c'),(ca,ca'+ac',c'a'),(ab,ab'+a'b,a'b')| is equal to

    Text Solution

    |