Re: Mathematica Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg66381] Re: Mathematica Question*From*: "Scout" <Scout at nodomain.com>*Date*: Thu, 11 May 2006 02:15:20 -0400 (EDT)*References*: <e3shhl$m39$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

"Bharat Bhole" <bbhole at gmail.com> news:e3shhl$m39$1 at smc.vnet.net... > Hello: > > Is there a way in Mathematica to check whether an algebraic expression is > positive or negative, and a way to specify conditions on the variables in > the expression? For example, is there a way to check whether x^2 is > positive > for any real x? I want to check this for a complicated > expression...basically the sign of the second derivative of a function. > > Thank you very much for your help. > > Bharat. > > Hi Bharat, I suppose that you need the Simplify[] command. In[1]:= Simplify[x^2 >= 0, x \[Element] Reals] Out[1]= True In[2]:= f[x_] := x^3; In[3]:= Simplify[{f[x] > 0, f''[x] > 0}, x > 0] Out[3]= {True, True} In[4]:= Simplify[{f[x] > 0, f''[x] > 0}, x < 0] Out[4]= {False, False} Hope this helps, ~Scout~