question

*To*: mathgroup at smc.vnet.net*Subject*: [mg77935] question*From*: dimitris <dimmechan at yahoo.com>*Date*: Wed, 20 Jun 2007 05:28:38 -0400 (EDT)

Hi. Say o=(16-x^2)^(1/2)-(4-x)^(1/2)*(4+x)^(1/2); In another CAS one must use assumptions in order to simplify >o:=sqrt(16-x^2)-sqrt(4-x)*sqrt(4+x); > combine(u) assuming x>-4,x<4 ; > simplify(%); 2 1/2 1/2 1/2 o := (16 - x ) - (4 - x) (4 + x) 2 1/2 1/2 (16 - x ) - ((4 - x) (4 + x)) 0 In Mathematica one simply gets In[10]:= Simplify[o] Out[10]= 0 I would like to hear your comments on this issue. Dimitris

**Follow-Ups**:**Re: question***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>