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Re: Calculating derivate in Mathematica 9 giving wrong result


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.





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