Graphe et python.

def descente_f():
    alpha = 0.1
    x=1/2
    l=[x]
    for i in range(100):
        x=x-alpha*(2*x+x**3)
        l.append(x)
    
    plt.figure()
    plt.semilogy(l)
    plt.show()
    
    X = np.linspace(-10,10, num = 101)
    Y = [ x**2 -1/4*x**4 for x in X ]
    Z = [ x**2 -1/4*x**4 for x in l ]
    plt.figure()
    plt.plot(X,Y)
    plt.plot(X,Z, 'o')
    plt.show()