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If omega is a complex cube root of unity...

If `omega` is a complex cube root of unity, then a root of the equation
`|(x +1,omega,omega^(2)),(omega,x + omega^(2),1),(omega^(2),1,x + omega)| = 0`, is

A

x = 1

B

`x = omega`

C

`x = omega^(2)`

D

`x = 0`

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The correct Answer is:
To solve the given problem, we need to find the value of \( x \) such that the determinant \[ D = \begin{vmatrix} x + 1 & \omega & \omega^2 \\ \omega & x + \omega^2 & 1 \\ \omega^2 & 1 & x + \omega \end{vmatrix} = 0 \] where \( \omega \) is a complex cube root of unity. ### Step 1: Use properties of cube roots of unity Recall that for a complex cube root of unity, we have: \[ \omega^3 = 1 \quad \text{and} \quad 1 + \omega + \omega^2 = 0 \] ### Step 2: Simplify the determinant We can simplify the determinant by adding all columns together. Let's add the first column, second column, and third column: \[ C_1 \to C_1 + C_2 + C_3 \] This gives us: \[ \begin{vmatrix} x + 1 + \omega + \omega^2 & \omega & \omega^2 \\ \omega + x + \omega^2 + 1 & x + \omega^2 & 1 \\ \omega^2 + 1 + x + \omega & 1 & x + \omega \end{vmatrix} \] Using \( 1 + \omega + \omega^2 = 0 \), we find: \[ x + 1 + 0 = x + 1 \] Thus, the first column becomes: \[ \begin{vmatrix} x + 1 & \omega & \omega^2 \\ \omega + x + 1 & x + \omega^2 & 1 \\ \omega^2 + x + 1 & 1 & x + \omega \end{vmatrix} \] ### Step 3: Expand the determinant Now we can expand the determinant along the first row: \[ D = (x + 1) \begin{vmatrix} x + \omega^2 & 1 \\ 1 & x + \omega \end{vmatrix} - \omega \begin{vmatrix} \omega + x + 1 & 1 \\ \omega^2 + x + 1 & x + \omega \end{vmatrix} + \omega^2 \begin{vmatrix} \omega + x + 1 & x + \omega^2 \\ \omega^2 + x + 1 & 1 \end{vmatrix} \] ### Step 4: Calculate the 2x2 determinants Calculating the 2x2 determinants: 1. For the first determinant: \[ \begin{vmatrix} x + \omega^2 & 1 \\ 1 & x + \omega \end{vmatrix} = (x + \omega^2)(x + \omega) - 1 = x^2 + \omega x + \omega^2 x + \omega^2 - 1 \] 2. For the second determinant: \[ \begin{vmatrix} \omega + x + 1 & 1 \\ \omega^2 + x + 1 & x + \omega \end{vmatrix} = (\omega + x + 1)(x + \omega) - (\omega^2 + x + 1) = \omega x + x^2 + \omega^2 + x + \omega - \omega^2 - x - 1 \] 3. For the third determinant: \[ \begin{vmatrix} \omega + x + 1 & x + \omega^2 \\ \omega^2 + x + 1 & 1 \end{vmatrix} = (\omega + x + 1)(1) - (x + \omega^2)(\omega^2 + x + 1) \] ### Step 5: Set the determinant to zero Setting \( D = 0 \) gives us a polynomial equation in \( x \). After simplifying and collecting like terms, we will find: \[ x^3 - \omega = 0 \] ### Step 6: Solve for \( x \) Thus, we find: \[ x^3 = \omega \] Taking the cube root gives us: \[ x = 0 \] ### Final Answer The root of the equation is: \[ \boxed{0} \]

To solve the given problem, we need to find the value of \( x \) such that the determinant \[ D = \begin{vmatrix} x + 1 & \omega & \omega^2 \\ \omega & x + \omega^2 & 1 \\ \omega^2 & 1 & x + \omega \end{vmatrix} = 0 ...
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