import matplotlib.pyplot as plt
import numpy as np

def f(x) :
    return x**4-(5/6)*x**3-(10/3)*x**2+(25/6)*x-1
X = np.linspace(-2.2,2,1000)
plt.plot(X,f(X))
plt.grid()
plt.show()

## Détermination des 4 racines par dichotomie
def dichotomie(f,a,b,epsilon) :
    fa = f(a)
    fb = f(b)
    largeur = b-a
    while largeur > epsilon :
        c=(a+b)/2
        fc = f(c)
        if fa*fc < 0:
            b=c
            fb=fc
        else:
            a=c
            fa=fc
        largeur = b-a
    return c
epsilon =1e-12
print(dichotomie(f,-2.1,-1.8,epsilon))
print(dichotomie(f,0,0.5,epsilon))
print(dichotomie(f,0.9,1.2,epsilon))
print(dichotomie(f,1.3,1.6,epsilon))