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Re: Transcendental functions

• To: mathgroup at smc.vnet.net
• Subject: [mg126300] Re: Transcendental functions
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Sun, 29 Apr 2012 02:12:12 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201204280925.FAA00665@smc.vnet.net>
• Reply-to: murray at math.umass.edu

    TrigToExp[ ArcTan[x] ]
(I/2)*Log[1 - I*x] - (I/2)*Log[1 + I*x]

Depending on when you want to replace ArcTan by its complex Log 
equivalent, you might handle an expression involving it so:

   func[ArcTan[x]] /. ArcTan[z_] :> TrigToExp[ArcTan[z]]

On 4/28/12 5:25 AM, David Egan wrote:
> Hi,
> I am trying to teach mathematica to recognize this function
>
>    ArcTan[x] - I/2 Log [(I + x)/(I - x)] == 0
>
> Any thoughts on how to force mathematica to use it in simplifications.
> Thanks
> David
>

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

• References:
  • Transcendental functions
    • From: David Egan <davee62@earthlink.net>