Find the general solution

Submitted by alpha on Tue, 01/12/2010 - 04:15.

$\tan\theta+\tan(\theta+\frac{\pi}{3})+\tan(\theta+\frac{2\pi}{3})=-3\tan\theta \tan(\theta+\frac{\pi}{3})\tan(\theta+\frac{2\pi}{3})=0$