On Thu, 23 Jun 2016 05:17 am, Ben Bacarisse wrote: > pdora...@pas-de-pub-merci.mac.com (Pierre-Alain Dorange) writes: > >> Ben Bacarisse <ben.use...@bsb.me.uk> wrote: >> >>> >>> math.atan2(INF, INF) >>> 0.7853981633974483 >>> >>> I would have expected NaN since atan2(INF, INF) could be thought of as >>> the limit of atan2(x, y) which could be any value in the range. And I'd >>> have guessed atan2(0, 0) would have been NaN too but >> >> i'm not a math expert, but the limit of atan2 would be 45°, so pi/4 >> radians (0,7854). >> As x,y are coordinates, the both infinite would tend toward 45°. > > The limit of atan2(x, x) is as you describe, but there is no reason to > pick that one case.
Given: x = INF y = INF assert x == y there is a reason to pick atan2(y, x) = pi/4: Since x == y, the answer should be the same as for any other pair of x == y. It might not be a *great* reason, but it's a reason. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
