Re: [math-fun] Trig puzzle

Thanks to all the info I learned from this thread, I now know how to find/construct interesting trig puzzles. The one I find beautiful and not close to anything I found on the Internet (in particular, not on http://mathworld.wolfram.com/TrigonometryAnglesPi13.html ) is tan(4*pi/13) + 4*sin(pi/13) = sqrt(13 - 2*sqrt(13)). Warut :)