<p>I don’t think there is one. I could be way off, but:
(cos30d+isin30d) = (rt3/2+i/2)
(rt3/2+i/2)^n = 1
log base(rt3/2+i/2) 1 = n
log(1)/log(rt3/2+i/2) = n
Punch that into a calculator in a+bi mode and you’ll get 0. I tried solving it with de Moivre’s Theorem and ended up with 0 again.</p>