def f(x):
    return (1 - math.cos(x)) / pow(x, 2)

xs = [x for x in np.arange(-3.0, 3.0, 0.05) if abs(x) > 0.05]
ys = [f(x) for x in xs]
#plt.plot(xs, ys, 'bo')


def f2(x):
    return 1/2-x**2/24+x**4/720-x**6/40320

num = 0.00000001

cN_f=abs(num*(num*math.sin(num)+2*math.cos(num)-2)/num**3/(1-math.cos(num)/num**2))
cN_f2=abs(num*((-1)*(num**5)/6720)+num**3/180-num/12)/f2(num))