Date: Apr 21, 2013 5:17 AM
Author: Alex Krasnov
Subject: Re: Mathematica integration Vs Sympy
Mathematica's Integrate implicitly assumes that parameters have generic

values. The result can be invalid for special values, in this case, a==1.

It appears that the same is true for SymPy's integrate, as u.subs({a:1})

demonstrates.

For other values, the Mathematica and SymPy results appear to differ by

a constant of integration. Both results are valid. This is a consequence

of different integration procedures and can occur even for the same

integral in different forms in Mathematica and presumably SymPy.

Alex

On Sat, 20 Apr 2013, Sergio R 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

>