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# De Moivre's Theorem watch

1. I have a question that I am not sure how to answer and it is:

Use De Moivre's Theorem for the following

z = 2(2+j)^4

Any help?
2. (Original post by IamLiquid)
I have a question that I am not sure how to answer and it is:

Use De Moivre's Theorem for the following

z = 2(2+j)^4

Any help?
you need to write in the form

start with finding the value of theta when (ie cosx is double the value of sinx)
3. 2(2+i) = z^(1/4)

Find e^(i n theta) at 4 points.
4. Square the bottom eqn on both sodes then let 4sinsquared(0) equal 2 x2sinsquares theta and use the half angle formula. This way you should be able to factorise rather than using cos20+sin20 = 1
Sorry the syntax is messed up

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