(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Use Demoivre's Theorem to evaluate w^2, if w=3(cos30degs+ising30degs)

PS, it's really pi/6, but I converted it to 30 degrees since I can't write on the screen..

2. Relevant equations

z^n=r^n(cos n*theta + i sin n*theta)

3. The attempt at a solution

w^2=3^2 (cos 2*30degs + i sin 2*30degs_

w^2=9(cos60degs+isin60degs)

w^2=9(0.5+i [square root of 3]/2)

w^2=(9/2)+9i[square root of 3]/2

===

I copied the test review answer key.. but I'm not sure if I copied it down right..

The answer that I copied down was

9[square root of 3]/2 + i9[square root of 3]/2..

That answer would like like it would come from a 45deg thing.. but sinn and cosn are 60degs..

Just making sure.. So has anyone seen where I went wrong?

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# Homework Help: Demoivre's Theorem: Am I doing it right?

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