The problem is the 1/8. I Python 2, this evaluates to 0, because of integer division. I recommend using Python 3, or if you must use Python 2, use "from __future__ import division". That will cause 1/8 to evaluate to the float 0.125.
For SymPy, it is best to use rational numbers, like Rational(1, 8). See also http://docs.sympy.org/latest/tutorial/gotchas.html#two-final-notes-and. Aaron Meurer On Wed, Feb 1, 2017 at 10:38 AM, Lorenzo Isella <[email protected]> wrote: > Dear All, > I am making my first baby steps with sympy and I must be > misunderstanding something. > I want to simplify the expression > > (N**2/8 -1/8)/((N-1)/2) hence this is what I do in a ipython shell > > n [2]: from sympy import * > > In [3]: var("N") > Out[3]: N > > In [4]: simplify((N**2/8 -1/8)/((N-1)/2)) > Out[4]: N**2/(4*(N - 1)) > > however, the right result is (N+1)/4. > > It is not rocket science, so what (obvious) thing am I missing? > Many thanks > > Lorenzo > > -- > 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 https://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/20170201153814.GA3881%40chicca. > 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 https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6K36YQchCt%3D1EA9XKHF7pwcL%2BtNdUQcySajxpY3ioCyRg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
