Re: FullSimplify doesn't simplify

*To*: mathgroup at smc.vnet.net*Subject*: [mg32780] Re: FullSimplify doesn't simplify*From*: lalu_bhatt at yahoo.com (Bhuvanesh)*Date*: Sat, 9 Feb 2002 05:11:57 -0500 (EST)*References*: <a404nb$bqk$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

"Ken Morgan" <kmorga51 at calvin.edu> wrote: > Does anyone know why Mathematica doesn't simplify the following to True? > > > In[1] := FullSimplify[(x y)^n == (x^n)(y^n)] > > Out[1] := (x y)^n == (x^n)(y^n) > > Are there cases where this is not true? > > > Thanks, > Ken Morgan > kmorga51 at calvin.edu It is apparently not true when both x and y are negative and n is not an integer: In[1]:= (x y)^n - (x^n)(y^n) /. {x->-1, y->-2, n->1/2} Out[1]= 2 Sqrt[2] In[2]:= FullSimplify[(x y)^n - (x^n)(y^n), n \[Element] Integers] Out[2]= 0 In[3]:= FullSimplify[(x y)^n - (x^n)(y^n), x>0] Out[3]= 0 -- Bhuvanesh, Wolfram Research.