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# Fp3 watch

1. Hi all,

Can anyone help me do this question on nth roots of unity?

z^3 = -8, giving the answer in the form a + bi

Thanks,
2. Write in the form , where . Then, you can add to the argument and the number remains unchanged. Can you find three numbers in the form which all equal -8? Then, you can take the 3rd root of them using your normal laws of indices, then use Euler's identity to find them in the form .

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3. z^3 + 8 = 0. Spot the obvious root and then factorize.

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