Re: Simplifying Log to ArcCos Expressions

*To*: mathgroup at smc.vnet.net*Subject*: [mg56882] Re: Simplifying Log to ArcCos Expressions*From*: "Peltio" <peltio at trilight.zone>*Date*: Mon, 9 May 2005 01:46:03 -0400 (EDT)*References*: <d5kapv$299$1@smc.vnet.net>*Reply-to*: "Peltio" <peltioNOSPAM at despammed.com.invalid>*Sender*: owner-wri-mathgroup at wolfram.com

"David Park" wrote >Dear MathGroup, > >I want to integrate the following expression and get a simple answer. > >expr1 = (k/r^2)*(1/Sqrt[1 - k^2/r^2]) > >The answer is actually quite simple: ArcCos[k/r] + constant. But what a lot of work for me to get it! Perhaps someone can show a simpler path. If I'm not mistaken, this is easily done by substitution. http://www.math.hmc.edu/calculus/tutorials/trig_substitution/ Simplification should be done before calling Integrate, then. cheers, Peltio Sometimes, the best way to use Mathematica is to not use it at all. : ] -- Invalid address in reply-to. Crafty deminging required to mail me.