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If i=sqrt(-1) and (1)^(1//4) = 1, omega ...

If `i=sqrt(-1) and (1)^(1//4) = 1, omega , omega^(z) , omega^3` then
`Delta=|(1,omega,omega^2,omega^3),(omega,omega^2,omega^3,1),(omega^2,omega^3,1,omega),(omega^3,1,omega,omega^2)|` is equal to

A

`i`

B

`-i`

C

1

D

0

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to calculate the determinant \( \Delta \) given by: \[ \Delta = \begin{vmatrix} 1 & \omega & \omega^2 & \omega^3 \\ \omega & \omega^2 & \omega^3 & 1 \\ \omega^2 & \omega^3 & 1 & \omega \\ \omega^3 & 1 & \omega & \omega^2 \end{vmatrix} \] where \( \omega \) is a primitive 4th root of unity, meaning \( \omega = e^{i\frac{\pi}{2}} = i \) and \( \omega^4 = 1 \). ### Step 1: Understanding the Roots of Unity The roots of unity are: - \( 1 \) - \( \omega = i \) - \( \omega^2 = -1 \) - \( \omega^3 = -i \) ### Step 2: Setting Up the Determinant We can rewrite the determinant using the values of \( \omega \): \[ \Delta = \begin{vmatrix} 1 & i & -1 & -i \\ i & -1 & -i & 1 \\ -1 & -i & 1 & i \\ -i & 1 & i & -1 \end{vmatrix} \] ### Step 3: Performing Column Operations To simplify the determinant, we can perform column operations. We can add all columns together to the first column: \[ C_1 \rightarrow C_1 + C_2 + C_3 + C_4 \] This gives us: \[ C_1 = 1 + i - 1 - i = 0 \] \[ C_2 = i - 1 - i + 1 = 0 \] \[ C_3 = -1 - i + 1 + i = 0 \] \[ C_4 = -i + 1 + i - 1 = 0 \] ### Step 4: Resulting Determinant After performing the column operations, we find that the first column becomes zero. Therefore, the determinant simplifies to: \[ \Delta = \begin{vmatrix} 0 & 0 & 0 & 0 \\ \text{...} & \text{...} & \text{...} & \text{...} \\ \text{...} & \text{...} & \text{...} & \text{...} \\ \text{...} & \text{...} & \text{...} & \text{...} \end{vmatrix} = 0 \] ### Conclusion Thus, the value of \( \Delta \) is: \[ \Delta = 0 \]
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{[(1,omega,omega^(2)),(omega,omega^(2),1),(omega^(2),1,omega)] + [(omega,omega^(2),1),(omega^(2),1,omega),(omega,omega^(2),1)]} [(1),(omega),(omega^(2))]

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If 1,omega , omega^2 are the cube roots of unity , then Delta=|(1,omega^n , omega^(2n)),(omega^n , omega^(2n), 1),(omega^(2n), 1, omega^n)| is equal to :

If 1,omega , omega^2 are the cube roots of unity , then Delta=|(1,omega^n , omega^(2n)),(omega^n , omega^(2n), 1),(omega^(2n), 1, omega^n)| is equal to :

ML KHANNA-DETERMINANTS -Self Assessment Test
  1. If i=sqrt(-1) and (1)^(1//4) = 1, omega , omega^(z) , omega^3 then D...

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

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  3. |(b+c,a,a),(b,c+a,b),(c,c,a+b)|=

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  4. |(1,1,1),(a,b,c),(a^3,b^3,c^3)|=

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  5. |(1/a,a^2,bc),(1/b,b^2,ca),(1/c,c^2,ab)|=

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  6. If x=-9 is a root of |(x,3,7),(2,x,2),(7,6,x)|=0 then other two roots ...

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  7. The solution of the equation |(x,2,-1),(2,5,x),(-1,2,x)| = 0 are

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  8. The roots of the equation |(0,x,16),(x,5,7),(0,9,x)| = 0 are

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  9. |(a+b,b+c,c+a),(b+c,c+a,a+b),(c+a,a+b,b+c)|=k|(a,b,c),(b,c,a),(c,a,b)|...

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  10. A root of the equation |(3-x,-6,3),(-6,3-x,3),(3,3,-6-x)| = 0

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  11. If |(-a^2,ab,ac),(ab,-b^2,bc),(ac,bc,-c^2)|=ka^2b^2c^2 , then k =

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  12. If omega!=1 is a cube root of unity and Delta=|(x+omega^(2),omega,1)...

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  13. |((a^x+a^(-x))^2,(a^x-a^(-x))^(2),1),((b^x+b^(-x))^2,(b^x-b^(-x))^(2),...

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  14. The number of values of k which the linear equations 4x+ky+2z=0 kx...

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  15. The value of k for which the set of equationsx + ky + 3z=0, 3x + ky – ...

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  16. If x + y +z=0, 4x+3y -z=0 and 3x + 5y +3z=0 is the given system of equ...

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  17. The system of equations x + y + z=2, 3x – y +2z=6 and 3x + y +z=-18 ha...

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  18. The system of equations x+y+z=6, x+2y + 3z= 10, x+2y + lamdaz=mu has n...

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  19. The system of linear equations x1 + 2x2 + x3 = 3, 2x1 + 3x2 + x3 = 3...

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  20. Let a,b,c be such that b(a+c) ne 0 . If |(a,a+1,a-1),(-b,b+1,b-1),(c...

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