Re: Simplification and Arg[]
- To: mathgroup at smc.vnet.net
- Subject: [mg66599] Re: Simplification and Arg[]
- From: "Jaccard Florian" <Florian.Jaccard at he-arc.ch>
- Date: Mon, 22 May 2006 18:14:30 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
hello!
I must admit it is difficult to guess...
ComplexExpand[Arg[a + b*I], TargetFunctions ->
{Re, Im}]
gives ArcTan[a, b]
ComplexExpand[Arg[1 + I*x] + Arg[1 - I*x],
TargetFunctions -> {Re, Im}]
gives 0
Regards
F.Jaccard
________________________________
De: Andrew Moylan [mailto:andrew.moylan at anu.edu.au]
=C0: mathgroup at smc.vnet.net
Objet : [heur] [mg66593] Simplification and Arg[]
Should Mathematica be able to simplify the following expression? (It is
easily seen to be zero under the given condition, x > 0.)
FullSimplify[
Arg[1 + I * x] + Arg[1 - I * x],
{x > 0}
]
In particular, I would have expected the following to yield ArcTan[b /
a], from which the above expression is easily reduced to zero:
FullSimplify[
Arg[a + I b],
{a > 0, b > 0}
]
Any ideas?
Cheers,
Andrew
P.S. Apologies if I have sent this twice; my original message seems not
to have worked.