SOLUTION: find all the nth root of -1

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Question 9264: find all the nth root of -1
Answer by mathmaven53(29) About Me  (Show Source):
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We use Demoivre's Theorem
(cos a + i sin a)^(1/n) = cos[(2k pi + a)/n] + i sin[(2k pi + a)/n]
for k = 0,1,...,n-1
we have -1 = cos pi + i sin pi
Now substitute into Demoivre's theorem using a = pi