Abs function error on python jupyter

[fenixjose]

From this program.............

num = 4
x, u = symbols('x u')
Irr = Function('Irr')(u)
Irr = 4*pi**2*u**2*Abs(integrate(0.25*(1-cos(2*pi*x*num))*exp(-I*2*pi*u*x), (x, 0, 1)))**2 # Notice the use of Abs function.
print(N(Irr.subs(u,1.1)))

The result is ..................

0.0279388389446924 + 1.23479674389006e-24*I
But it is supposed to be a real number, not a complex, even with an imaginary part close to zero !!!

On the other hand, the same program on PyCharm - Python 3.5 is  0.0279388389446924 (just real number)

Am I doing something wrong?

My system is.............
The version of the notebook server is 4.2.3 and is running on:
Python 3.5.2 |Anaconda 4.2.0 (64-bit)| (default, Jul  2 2016, 17:53:06) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]

[Paul Hobson]

Where did you define the 

"symbols", "Function", "Abs" and "I" objects?

-p

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[Thomas Kluyver]

I guess you're using sympy? You may need to ask a sympy mailing list. Jupyter shouldn't be affecting what your code actually does, but it may be that your code finds a different version of sympy.

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