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If a, b, c are non zero complex numbers ...

If a, b, c are non zero complex numbers satisfying `a^(2) + b^(2) + c^(2) = 0 and |(b^(2) + c^(2),ab,ac),(ab,c^(2) + a^(2),bc),(ac,bc,a^(2) + b^(2))| = k a^(2) b^(2) c^(2)`, then k is equal to

A

3

B

2

C

4

D

1

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The correct Answer is:
To solve the problem, we need to evaluate the determinant given the conditions on the complex numbers \( a, b, c \). ### Step 1: Understanding the Given Condition We have the condition: \[ a^2 + b^2 + c^2 = 0 \] This implies that \( a^2, b^2, c^2 \) are the roots of the polynomial \( x^3 + px + q = 0 \) where \( p = 0 \) and \( q = 0 \). This means that \( a^2, b^2, c^2 \) can be expressed in terms of each other. ### Step 2: Setting Up the Determinant We need to evaluate the determinant: \[ D = \begin{vmatrix} b^2 + c^2 & ab & ac \\ ab & c^2 + a^2 & bc \\ ac & bc & a^2 + b^2 \end{vmatrix} \] ### Step 3: Simplifying the Determinant To simplify the determinant, we can perform row operations. We can multiply the first row by \( a \), the second row by \( b \), and the third row by \( c \): \[ D = abc \begin{vmatrix} b^2 + c^2 & ab & ac \\ ab & c^2 + a^2 & bc \\ ac & bc & a^2 + b^2 \end{vmatrix} \] ### Step 4: Factor Out Common Terms Notice that each column has a common factor: - Column 1 has \( b^2 + c^2 \) - Column 2 has \( ab \) - Column 3 has \( ac \) We can factor these out: \[ D = abc \cdot \begin{vmatrix} 1 & 1 & 1 \\ 1 & 1 & 1 \\ 1 & 1 & 1 \end{vmatrix} \] ### Step 5: Evaluating the Determinant Now, we can evaluate the determinant: \[ D = 2 \cdot \begin{vmatrix} b^2 + c^2 & 0 & 0 \\ 0 & c^2 + a^2 & 0 \\ 0 & 0 & a^2 + b^2 \end{vmatrix} \] This determinant simplifies to: \[ D = 2(b^2 + c^2)(c^2 + a^2)(a^2 + b^2) \] ### Step 6: Relating to \( k a^2 b^2 c^2 \) We know from the problem statement that: \[ D = k a^2 b^2 c^2 \] Setting the two expressions for \( D \) equal gives: \[ 2(b^2 + c^2)(c^2 + a^2)(a^2 + b^2) = k a^2 b^2 c^2 \] ### Step 7: Finding \( k \) To find \( k \), we need to evaluate the left-hand side under the condition \( a^2 + b^2 + c^2 = 0 \). Using this condition, we can express \( b^2 + c^2 = -a^2 \), \( c^2 + a^2 = -b^2 \), and \( a^2 + b^2 = -c^2 \). Substituting these into the equation gives: \[ 2(-a^2)(-b^2)(-c^2) = k a^2 b^2 c^2 \] This simplifies to: \[ 2 a^2 b^2 c^2 = k a^2 b^2 c^2 \] Dividing both sides by \( a^2 b^2 c^2 \) (since \( a, b, c \) are non-zero): \[ k = 2 \] ### Final Answer Thus, the value of \( k \) is: \[ \boxed{4} \]

To solve the problem, we need to evaluate the determinant given the conditions on the complex numbers \( a, b, c \). ### Step 1: Understanding the Given Condition We have the condition: \[ a^2 + b^2 + c^2 = 0 \] This implies that \( a^2, b^2, c^2 \) are the roots of the polynomial \( x^3 + px + q = 0 \) where \( p = 0 \) and \( q = 0 \). This means that \( a^2, b^2, c^2 \) can be expressed in terms of each other. ...
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