In [12]:
import scipy
import numpy as np
import matplotlib.pylab as pl
t = np.linspace(0,3*np.pi,500)
pl.plot(t,np.exp(-t)*np.cos(2*np.pi*t))
for i in range(1,10,2):
q = i/4.0
pl.plot(q,np.exp(-q)*np.cos(2*np.pi*q),'ro')
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