Well, if it doesn't matter maybe you can figure it out. Solver(cos X = (y^2 + z^2 - x^2) / (2yz),X,0.5) I do that and i have 0 already in X, and it tells me my guess is bad or something. I think error message 29. What's up with that? Alex Visit my homepage at: http://www.fortunecity.com/skyscraper/coding/190/index.html Or email me at: kimo@iland.net