More questions that I can't seem to get.
Question 4:
z^n = 2^n * [ cos(5npi/6) + isin(5npi/6) ], by De Moivre's Theorem.
For z^n to be real, Im(z) = 0:
sin(5npi/6) = 0
5npi/6 = 0
Now its asking for lowest positive integer value, for the sin component to be 0, the value inside it must be pi. Hence n is 6 since it is the lowest positive integer value that produces 0.
I'll solve Q2 after my online school finishes today but I have an idea for it.