Re: Re: How to simplify to a result that is real

*To*: mathgroup at smc.vnet.net*Subject*: [mg50752] Re: [mg50725] Re: How to simplify to a result that is real*From*: DrBob <drbob at bigfoot.com>*Date*: Sun, 19 Sep 2004 03:56:00 -0400 (EDT)*References*: <cidt38$brv$1@smc.vnet.net> <200409180948.FAA00517@smc.vnet.net>*Reply-to*: drbob at bigfoot.com*Sender*: owner-wri-mathgroup at wolfram.com

But that's not what MY 5.0.1.0 says: Integrate[1/(1 + e*Cos[t]), {t, 0, a}, Assumptions -> {-1 < e < 1, 0 < a < Pi}] -((1/Sqrt[1 - e^2])*(I*Log[Sqrt[1 - e^2] - I*(-1 + e)*Tan[a/2]])) + (1/Sqrt[1 - e^2])*(I*Log[Sqrt[1 - e^2] + I*(-1 + e)*Tan[a/2]]) Bobby On Sat, 18 Sep 2004 05:48:16 -0400 (EDT), Jens-Peer Kuska <kuska at informatik.uni-leipzig.de> wrote: > Hi, > > my Mathematica 5.0.1 say > > (-2*ArcTan[((-1 + e)*Tan[a/2])/Sqrt[1 - e^2]])/ > Sqrt[1 - e^2] > > and it looks real ? > > Regards > Jens > > Richard Chen wrote: >> >> The command: >> >> Integrate[1/(1 + e Cos[t]), {t, 0, a}, >> Assumptions -> {-1 < e < 1, 0 < a < Pi}] >> >> leads to a complex valued result. I could not make >> mathematica to render the result in a form that is >> purely real. ComplexExpand, Refine all do not seem to work. >> >> Does anyone know how to make mathematica to simplify this >> result into a real form? >> >> Thanks for any info. >> >> Richard > > > -- DrBob at bigfoot.com www.eclecticdreams.net

**References**:**Re: How to simplify to a result that is real***From:*Jens-Peer Kuska <kuska@informatik.uni-leipzig.de>