IB Maths AA HL Ahl 1 14 Hl Complex Roots and De Moivres Theorem Topic Practice

attempt to apply De Moivre's theorem
$(1-\cos 2 \theta-i \sin 2 \theta)^{\frac{1}{3}}=2^{\frac{1}{3}}(\sin \theta)^{\frac{1}{3}}\left[\cos \left(\frac{\theta-\frac{\pi}{2}+2 n \pi}{3}\right)+i \sin \left(\frac{\theta-\frac{\pi}{2}+2 n \pi}{3}\right)\right]$
Note: A1 for modulus, A1 for dividing argument of z by 3 and A1 for $2 n \pi$.
Hence cube roots are the above expression when n=-1,0,1.
Equivalent forms are acceptable.
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