Re: Simplify problems for checking easy equalities...

*To*: mathgroup at smc.vnet.net*Subject*: [mg53914] Re: Simplify problems for checking easy equalities...*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Fri, 4 Feb 2005 04:11:09 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

On 2/2/05 at 6:25 AM, kjm at KevinMcCann.com (Kevin J. McCann) wrote: >While your approach works, the identity is true regardless of the >values of x and n; so, it is curious that Simplify does not get it >for the more general case. No, the identity is not true regardless of the values of x and n. For a specific counter example, choose x = -1 and n = 2. The Log[x^n] = Log[1] = 0 and n Log[x] = 2 Log[-1] = 2 Pi I which is clearly not 0. >David Park wrote: >>Cyrus, >> >>Include the proper assumptions in the Simplify statement. >> >>Simplify[Log[x^n] - n*Log[x], n \[Element] Integers && x > 0] 0 >> >>David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ >> >>From: Cyrus Erik Eierud [mailto:cyruserik at tele2.se] To: mathgroup at smc.vnet.net >> >>Please Help! >> >>Thanks for all great answers I've already found here! My problem >>is that I can not simplify what to me seems as a very simple >>equality task. This is what I want Mathematica to return zero for: >> >>in[1]:= FullSimplify[Log[x^n] - n*Log[x]] >> >>out[1]= -n Log[x] + Log[x^n]) >> >>I have used Simplify to check equalities, but the one above (and >>many other equations similar to the one above) just don't >>simplify. Am I doing anything wrong or does anyone know of a >>better way to check equalities? >> >>Appreciate any help, Cyrus Eierud, Student cyruserik at tele2.se >> >> >> > -- To reply via email subtract one hundred and four