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What is the value of |{:(" "1-i," "omeg...

What is the value of `|{:(" "1-i," "omega^(2)," "-omega),(" "omega^(2)+i," "omega," "-i),(1-2i-omega^(2),omega^(2)-omega,i-omega):}|`, where `omega` is the cube root of unity ?

A

-1

B

1

C

2

D

0

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The correct Answer is:
To find the value of the determinant \[ D = \begin{vmatrix} 1 - i & \omega^2 & -\omega \\ \omega^2 + i & \omega & -i \\ 1 - 2i - \omega^2 & \omega^2 - \omega & i - \omega \end{vmatrix} \] where \(\omega\) is a cube root of unity, we can follow these steps: ### Step 1: Understand the properties of \(\omega\) The cube roots of unity are given by: \[ \omega = e^{2\pi i / 3} = -\frac{1}{2} + i\frac{\sqrt{3}}{2} \] and \[ \omega^2 = e^{-2\pi i / 3} = -\frac{1}{2} - i\frac{\sqrt{3}}{2} \] with the property that \(\omega^3 = 1\) and \(1 + \omega + \omega^2 = 0\). ### Step 2: Simplify the determinant We can perform row operations to simplify the determinant. Let's subtract the second row from the first row and then subtract the third row from the result: \[ R_1 = R_1 - R_2 \] This gives us: \[ D = \begin{vmatrix} (1 - i) - (\omega^2 + i) & \omega^2 - \omega & -\omega - (-i) \\ \omega^2 + i & \omega & -i \\ 1 - 2i - \omega^2 & \omega^2 - \omega & i - \omega \end{vmatrix} \] Calculating the new elements of the first row: 1. First element: \( (1 - i) - (\omega^2 + i) = 1 - \omega^2 - 2i \) 2. Second element: \( \omega^2 - \omega \) 3. Third element: \( -\omega + i \) So we have: \[ D = \begin{vmatrix} 1 - \omega^2 - 2i & \omega^2 - \omega & -\omega + i \\ \omega^2 + i & \omega & -i \\ 1 - 2i - \omega^2 & \omega^2 - \omega & i - \omega \end{vmatrix} \] ### Step 3: Further simplify the determinant Next, we can perform another operation to simplify further. Let's subtract the first row from the third row: \[ R_3 = R_3 - R_1 \] This gives us: 1. First element: \( (1 - 2i - \omega^2) - (1 - \omega^2 - 2i) = 0 \) 2. Second element: \( (\omega^2 - \omega) - (\omega^2 - \omega) = 0 \) 3. Third element: \( (i - \omega) - (-\omega + i) = 0 \) Thus, the third row becomes: \[ \begin{pmatrix} 0 & 0 & 0 \end{pmatrix} \] ### Step 4: Conclusion Since one row of the determinant is all zeros, the value of the determinant is: \[ D = 0 \] ### Final Answer The value of the determinant is \(0\).

To find the value of the determinant \[ D = \begin{vmatrix} 1 - i & \omega^2 & -\omega \\ \omega^2 + i & \omega & -i \\ 1 - 2i - \omega^2 & \omega^2 - \omega & i - \omega \end{vmatrix} ...
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