exo 13 curves

import matplotlib.pyplot as plt
from fractions import Fraction

W = [Fraction(1)]

def tracer(f, pts): plt.plot(pts, [f(x) for x in pts])

def W2p1(n):
    if n>=len(W):
        W.append(Fraction(2*n, 2*n+1)*W2p1(n-1))
    return W[n]

def phi(n): return lambda x: (1-x**2)**n/2/W2p1(n).real

def subdiv(n): return [-1+i*(2)/n for i in range(n)]
##
pts = subdiv(1000)
##
for n in range(500):
    tracer(phi(n), pts)
plt.show()