where

Now, use Euler's formula to find the 3 roots.

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- Dec 6th 2012, 06:18 PM #1

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- Dec 19th 2012, 08:51 AM #4
## Re: how to (-64i)^1/3?

- Dec 19th 2012, 09:09 AM #5

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- Dec 22nd 2012, 08:18 AM #11

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- Dec 22nd 2012, 12:49 PM #12

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## Re: how to (-64i)^1/3?

Did you consider putting k= 1 in the formula you are given?

If k= 0, as you say.

If k= 1,

If k= 2,

If k= 3, which will give the same complex number as with k= 0 because sine and cosine (and so ) have period .