Re: Problems with simplify and Sqrt[a^2]

*To*: mathgroup at smc.vnet.net*Subject*: [mg73946] Re: Problems with simplify and Sqrt[a^2]*From*: Johan Grönqvist <johan.gronqvist at gmail.com>*Date*: Sat, 3 Mar 2007 01:16:11 -0500 (EST)*References*: <es907e$2b4$1@smc.vnet.net>

dshortho skrev: > any help on this one: > I would have thought Mathematica would have resolved Sqrt[v1^2] to v1 (!?) > Test this with v1=(-1) and you will see why it does not hold. What you may want is Sqrt[v1]^2 = v1, and mathematica does this. > Does anyone out there know why it does not do this, as it is causing some problems with some proofs I am doing ? > I think you want: Simplify[Sqrt[x^2], Assumptions -> x>0}]