import matplotlib.pyplot as plt

def Aire_trap(n):
    h=1/n
    x=0
    for k in range(n):
        b=f(x)
        B=f(x+h)
        # construction du trapèze
        trap=plt.plot([x,x,x+h,x+h,x],[0,f(x),f(x+h),0,0],color='orange')
        x=x+h
    # affichage    
    plt.show()