[math-fun] Think you're good at Trig?

I gave ries ArcTan[1/2]/ArcTan[1/3`22] and it quickly found. Cos[\[Pi]/(x + 1)] == 7/25 Quick, is that right?-) But interestingly, it can't do ArcTan[1/2]/ArcTan[1/4`22] There's probably a way to turn on arctrigs, but my manual is ancient. —rwg