Re: Calculating derivate in Mathematica 9 giving wrong result

*To*: mathgroup at smc.vnet.net*Subject*: [mg131414] Re: Calculating derivate in Mathematica 9 giving wrong result*From*: "Dave Snead" <dsnead6 at charter.net>*Date*: Wed, 3 Jul 2013 22:00:21 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130703090146.A8EAD6AD9@smc.vnet.net>

James, Both results are correct. The functions you are differentiating are different. Cheers, Dave Snead -----Original Message----- From: James Sent: Wednesday, July 03, 2013 2:01 AM To: mathgroup at smc.vnet.net Subject: [mg131414] Calculating derivate in Mathematica 9 giving wrong result In[5]:= D[(x^2 - 2)/(x^3 + 6), x] Out[5]= -((3 x^2 (-2 + x^2))/(6 + x^3)^2) + (2 x)/(6 + x^3) That is from Mathematica 9. The wolfram alpha site and my textbook give this answer: d/dx((x^2+x-2)/(x^3+6)) = (-x^4-2 x^3+6 x^2+12x+6)/(x^3+6)^2 Please tell me what I am doing wrong.

**References**:**Calculating derivate in Mathematica 9 giving wrong result***From:*James <jhlawley@gmail.com>