Re: Very strange behaviour of ArcTan
- To: mathgroup at smc.vnet.net
- Subject: [mg102682] Re: Very strange behaviour of ArcTan
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Tue, 18 Aug 2009 06:10:39 -0400 (EDT)
- References: <email@example.com>
On 2009.08.17. 14:06, Alexey wrote: > Hello, > I just have discovered some strange (buggy?) feature of ArcTan > function in Mathematica 5.2. Try the following; > > In:= > ArcTan[.5,$MachinePrecision] > ArcTan[.5] > > Out= > 1.53947 > > Out= > 0.463648 > > The expression ArcTan[.5,$MachinePrecision] must (?) give an error but > in really gives some strange output without any error messages... What > do you think about this? What are you trying to do? According to the docs, "ArcTan[x,y] gives the arc tangent of y/x, taking into account which quadrant the point (x,y) is in."