1.

Let `omega` be a complex number such that `2omega+1=z` where `z=sqrt(-3)`. If `|{:(1,1,1),(1,-omega^(2)-1,omega^(2)),(1,omega^(2),omega^(7))|=3k`, then k is equal to

Answer» Here, `z = sqrt (-3) = sqrt3i`
`:. 2omega+1 = sqrt3i`
`=>omega = (sqrt3i-1)/2`
Now, we will find the value of the given determinant.
`|[1,1,1],[1,-omega^2-1,omega^2],[1,omega^2,omega^7]|`
Now, we know, `1+omega+omega^2 = 0` amd `omega^3 = 1`So, our determinant becomes,
`|[1,1,1],[1,omega,omega^2],[1,omega^2,omega]|`
`=[omega^2-omega^4-omega+omega^2+omega^2-omega]`
`=[omega^2-omega-omega+omega^2+omega^2-omega]`
`=3(omega^2 - omega)`
`=3(-1/2-(sqrt3i)/2 + 1/2 - (sqrt3i)/2))`
`= -3sqrt3i`
`:. -3sqrt3i = 3k`
`=> k = -sqrt3i`
`=> k = -z.`


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