Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2013

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Mathematica integration Vs Sympy

  • To: mathgroup at smc.vnet.net
  • Subject: [mg130564] Re: Mathematica integration Vs Sympy
  • From: Brentt <brenttnewman at gmail.com>
  • Date: Sun, 21 Apr 2013 05:16:26 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • Delivered-to: l-mathgroup@wolfram.com
  • Delivered-to: mathgroup-newout@smc.vnet.net
  • Delivered-to: mathgroup-newsend@smc.vnet.net
  • References: <20130420094229.B63996A64@smc.vnet.net>

The result:

In[0]: Integrate[1/(x*(1 - a*(1 - x))), x]
 Out[0]: (Log[1 + a (-1 + x)] - Log[x])/(-1 + a)

Seems to be true for all complex a and x . Why do you think it assumes a>1?







On Sat, Apr 20, 2013 at 2:42 AM, Sergio R <sergiorquestion at gmail.com> wrote:

> Hello all,
>
>    Just for fun a put an integral I was doing via mathematica
> WolframAlpha
> [
> http://www.wolframalpha.com/input/?i=Integrate[1%2F%28x*%281-a*%281-x%29%29%29%2Cx]
> ]
> into the online sympy [ http://live.sympy.org/ ] console
> the following:
>
> a = Symbol('a'); g = 1/(x*(1-a*(1-x))) ; u=simplify(integrate(g,x))
>
> Then, to display the result, at the sympy ">>>" prompt, type u
> and hit return.
>
>   To my surprise,  sympy seems to give the right result without any
> assumption, while mathematica's result seems to assume a>1, which is
> not specified. Also for this case (a>1) sympy gives an extra constant
> which is not present in the mathematica result.
>
> Is there a way to make mathematica to output a general result like
> sympy
> in this case?
>
> Sergio
>
>




  • Prev by Date: Re: Mathematica integration Vs Sympy
  • Next by Date: Re: Find the function that best fits
  • Previous by thread: Re: Mathematica integration Vs Sympy
  • Next by thread: Re: Mathematica integration Vs Sympy