Thank you very much! On Monday, September 19, 2016 at 12:44:24 PM UTC-3, Aaron Meurer wrote: > > With that being said, either answer is wrong if you want a real function. > For that, you need log(abs(4 - t)). But unfortunately, the abs() answer > isn't valid in the general complex case, which is why SymPy doesn't return > it. > > Aaron Meurer > > On Mon, Sep 19, 2016 at 11:42 AM, Aaron Meurer <asme...@gmail.com > <javascript:>> wrote: > >> See https://github.com/sympy/sympy/issues/11017. It would be nice if we >> could fix ratint to not flip signs in the logarithm. >> >> Aaron Meurer >> >> On Mon, Sep 19, 2016 at 2:43 AM, Kalevi Suominen <jks...@gmail.com >> <javascript:>> wrote: >> >>> >>> There are several integrators in SymPy. The latter form is produced by >>> ratint. >>> >>> >>> from sympy.integrals.rationaltools import ratint >>> >>> from sympy.abc import t >>> >>> ratint(1/(4*(-t + 4)), t) >>> -log(t - 4)/4 >>> >>> Kalevi Suominen >>> >>> >>> On Monday, September 19, 2016 at 5:06:22 AM UTC+3, Raphael Timbó wrote: >>>> >>>> Since the images with the results are distorted: >>>> >>>> First result: >>>> >>>> -(1/4)*log(4*t - 16) >>>> >>>> Results given by the step-by=step solution on sympy gamma: >>>> >>>> -(1/4)*log(-t + 4) >>>> >>>> >>>> >>>> On Sunday, September 18, 2016 at 3:18:31 PM UTC-3, Raphael Timbó wrote: >>>>> >>>>> Hi, >>>>> I was trying to use: >>>>> integrate(Rational(1,4)*(1/(4-t))) >>>>> >>>>> This was returning: >>>>> −14log(4t−16) >>>>> >>>>> I was not expecting this result... I went to sympy gamma to see the >>>>> steps and I saw that: >>>>> >>>>> Antiderivative forms: >>>>> <http://gamma.sympy.org/input/?i=integrate%28Rational%281%2C4%29*%281%2F%284-t%29%29%29#integral_alternate_fake> >>>>> >>>>> - integrate(1/(4*(-t + 4)), t) >>>>> −14log(4t−16) >>>>> >>>>> >>>>> But when you check the steps you have: >>>>> >>>>> The answer is: >>>>> >>>>> −14log(−t+4)+constant >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> I could not understand why the results are different... >>>>> Any explanation? >>>>> >>>>> Thank you! >>>>> >>>>> -- >>> You received this message because you are subscribed to the Google >>> Groups "sympy" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to sympy+un...@googlegroups.com <javascript:>. >>> To post to this group, send email to sy...@googlegroups.com >>> <javascript:>. >>> Visit this group at https://groups.google.com/group/sympy. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/sympy/1629e59a-4d35-4927-89fc-0f3a94a3fd86%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/sympy/1629e59a-4d35-4927-89fc-0f3a94a3fd86%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >

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