Re: Rearrangement of expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg91748] Re: Rearrangement of expression*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Sun, 7 Sep 2008 05:35:19 -0400 (EDT)*References*: <g9t6np$j9n$1@smc.vnet.net>

Hi, expr = a/Sqrt[a^2 + b^2]; expr //. { (a^2 + q_)^(Rational[n_, 2]) :> Abs[a]^n*(1 + q/a^2)^(Rational[n, 2]), a_/Abs[a_] :> Sign[a]} Regards Jens Gehricht at googlemail.com wrote: > Hi! > > Suppose I have the fraction a/Sqrt[a^2+b^2]. How can I rearrange it to > 1/Sqrt[1+(b/a)^2]? > With thanks > Yours Wolfgang >