>>268
極形式使うならこんなん
{2(cosπ/3+isinπ/3)}^n+{2(cos5π/3+isin5π/3)}^n=32
2^n(cosπn/3+isinπn/3)+2^n(cos5πn/3+isin5πn/3)=32
2^n(cos2πn+isin2πn)=32
2^n=32
n=5