Re: Extract a part of expression

*To*: mathgroup at smc.vnet.net*Subject*: [mg124373] Re: Extract a part of expression*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Tue, 17 Jan 2012 05:59:59 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201201162207.RAA15301@smc.vnet.net>

expr = HoldForm[(x^2 Cos[x] (Sin[2 x] Tan[x]))/(E^x*x*Csc[x]^2)]; expr /. x_/y_ -> x // ReleaseHold x^2*Sin[x]*Sin[2*x] expr /. x_/y_ -> y // ReleaseHold E^x*x*Csc[x]^2 Bob Hanlon On Mon, Jan 16, 2012 at 5:07 PM, Miguel Gil <misvrne at gmail.com> wrote: > How I can extract the full numerator (or denominator) of an expression of the form g (x) / w (x)?. > I tried to do with Numerator [expr], but returns a wrong result. I tried with the attribute HoldForm [expr] and can not get the correct result. > > For example: > expr = (x ^ 2 Cos [x] (Sin [2x], Tan [x ]))/( E ^ x * x * Csc [x] ^ 2) >

**References**:**Extract a part of expression***From:*Miguel Gil <misvrne@gmail.com>