import matplotlib.pyplot as plt
import numpy as np
from scipy.optimize import bisect

def f(ksi,n,P) :
    return 27*(ksi**4)*(P**2)-31.7*(1+n+2*ksi)*(1+n+2*ksi)*(1-ksi)*(n-ksi)

## Détermination de la racine par la fonction bisect
P=30
print(bisect(f,0,1,args=(1,P)))
print(bisect(f,0,1,args=(2,P)))
print(bisect(f,0,1,args=(5,P)))

P=10
print(bisect(f,0,1,args=(1,P)))
print(bisect(f,0,1,args=(2,P)))
print(bisect(f,0,1,args=(5,P)))