The latter is incorrect, since when you integrate you get the wrong result (or the definite integral doesn't work).
That's a big bug, thanks for reporting it! On Tue, May 6, 2014 at 4:02 PM, Aaron Meurer <[email protected]> wrote: > Is the other result incorrect, or just more complicated? > > Aaron Meurer > > On Tue, May 6, 2014 at 12:20 PM, David Schueler <[email protected]> wrote: >> It seems that sympy cannot properly break apart functions for integration. >> >> Python 2.7.6 |Anaconda 1.9.1 (x86_64)| (default, Jan 10 2014, 11:23:15) >> Type "copyright", "credits" or "license" for more information. >> >> IPython 2.0.0 -- An enhanced Interactive Python. >> ? -> Introduction and overview of IPython's features. >> %quickref -> Quick reference. >> help -> Python's own help system. >> object? -> Details about 'object', use 'object??' for extra details. >> %guiref -> A brief reference about the graphical user interface. >> >> In [1]: from sympy import * >> >> In [2]: init_session() >> IPython console for SymPy 0.7.5 (Python 2.7.6-64-bit) (ground types: python) >> >> These commands were executed: >>>>> from __future__ import division >>>>> from sympy import * >>>>> x, y, z, t = symbols('x y z t') >>>>> k, m, n = symbols('k m n', integer=True) >>>>> f, g, h = symbols('f g h', cls=Function) >> >> Documentation can be found at http://www.sympy.org >> WARNING: Hook shutdown_hook is deprecated. Use the atexit module instead. >> >> >> >> In [5]: print integrate(expand((x-2)/sqrt(x)),(x,1,4)) >> 2/3 >> >> In [6]: print integrate((x-2)/sqrt(x),(x,1,4)) >> -6 >> >> The former is correct based on other calculations. >> >> Also: >> >> print integrate(expand((x-2)/sqrt(x)),x) >> 2*x**(3/2)/3 - 4*sqrt(x) >> >> print integrate((x-2)/sqrt(x),x) >> 2*sqrt(1 + 2/(x - 2))*(x - 2)**(7/2)/(6*x + 3*(x - 2)**2 - 12) - 4*sqrt(1 + >> 2/(x - 2))*(x - 2)**(5/2)/(6*x + 3*(x - 2)**2 - 12) - 16*sqrt(1 + 2/(x - >> 2))*(x - 2)**(3/2)/(6*x + 3*(x - 2)**2 - 12) + 8*sqrt(2)*(x - 2)**2/(6*x + >> 3*(x - 2)**2 - 12) + 16*sqrt(2)*(x - 2)/(6*x + 3*(x - 2)**2 - 12) >> >> Again, the former is correct. >> >> Thoughts? >> >> -- >> 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 [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/63e4d240-59d5-422f-b265-0b2b1895142f%40googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. > > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAKgW%3D6LAqdTZVa0Nn6uOR90SEnNrA_LxfOvccAjCf2p_tF1sRg%40mail.gmail.com. > For more options, visit https://groups.google.com/d/optout. -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CADDwiVD_hgEGgcPVNgS3L84tdxTb8qm4tkqtyxEP78N-JkZy5A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
