What if there's a 2 or 3 in front of Theta/X?
These are the worst -- cos3X-1=0, sin2X-2=0 -- and they're typically for honors students only. Believe me, I hate these as much as students do, and it took me a long time to figure out a good way to explain them. Luckily, that was a while back, so you get the fruits of my experience on this one! Still no fun, but if you drop your 360n or 2pi(n) in at the right time, it becomes a plug-and-chug affair.