Serie de Fourier de una onda triangular.

import pylab
import numpy as np
#Reconstruccion
A=1.
a0=1./2
t=np.linspace(-3,3,10000)
s_per=0
for k in range(-30,30):     
    #ak=((-1)^k-1)*A/(np.pi^2*k^2)
    if k!=0:
        s_per=s_per+((-1)**k-1)*A/(np.pi**2*k**2)*np.exp(1j*k*2*np.pi*t)
s_per=s_per+a0    
pylab.plot(t,s_per), pylab.show()
pylab.grid(True)