Re: Another question on Assuming

*To*: mathgroup at smc.vnet.net*Subject*: [mg85903] Re: Another question on Assuming*From*: "David W.Cantrell" <DWCantrell at sigmaxi.net>*Date*: Wed, 27 Feb 2008 04:27:14 -0500 (EST)*References*: <fq0to0$k3s$1@smc.vnet.net>

"Kevin J. McCann" <Kevin.McCann at umbc.edu> wrote: > The first example in the Mathematica Help on Assuming is (in part) > > Assuming[a > 0, Refine[Sqrt[a^2]]] > > which results in the answer a, as it should; however if I type instead > > Assuming[a > 0, Sqrt[a^2]] > > I get back Sqrt[a^2]], But you didn't ask that anything be _done_ to Sqrt[a^2]. Note that we can use Simplify instead of Refine: In[5]:= Assuming[a > 0, Simplify[Sqrt[a^2]]] Out[5]= a > but I should get a, since there is no other correct answer, No. Sqrt[a^2] is correct also; it's just not as simple as you want. David > because the assumption that a > 0 implies that it a is a > positive real. > > Bug? > > Kevin