Very Basic Question on Simplify

[Lorenzo Isella]

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

[Aaron Meurer]

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

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