RE: Limit and Abs

*To*: mathgroup at smc.vnet.net*Subject*: [mg31212] RE: [mg31194] Limit and Abs*From*: Bradley Stoll <BradleyS at Harker.org>*Date*: Fri, 19 Oct 2001 03:12:02 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

That's interesting. When I evaluate Limit[Abs[Cot[a]]/(Abs[Cot[a]] + 2), a -> Infinity], Mathematica returns 1, which does not make sense when you view the graph. When I evaluate Limit[Cot[a]/(Cot[a] + 2), a -> Infinity], Mathematica returns Abs[Cot[a]]/(2 + Abs[Cot[a]]). Can someone explain this? By the looks of it, neither of these limits exist, which is what I would've thought in the first place. I'm using 4.1, by the way. Bradley Stoll -----Original Message----- From: Oliver Friedrich [mailto:oliver.friedrich at tz-mikroelektronik.de] To: mathgroup at smc.vnet.net Subject: [mg31212] [mg31194] Limit and Abs Hallo, if I evaluate Limit[Cot[a]/(Cot[a]+2),a->Infinity] i get the correct answer. But I want to evaluate Limit[Abs[Cot[a]]/(Abs[Cot[a]]+2),n->Infinity] and that's being returned unevaluated. Help states, that Limit will return expressions unevaluated, if there are functions with unknown behaviour (Abs unknown ??) so I'm not too surprised or disappointed. But anyway, how can I workaround or bypass this problem, maybe an option or another function in the extra packages ? Thanks Oliver Friedrich