from math import log
def f(x):
    return (log(x))

def rect(n,a,b):
    s=0
    S=0
    h=(b-a)/n
    for k in range(n):
        s=s+f(a+k*h)*h
        S=S+f(a+(k+1)*h)*h
    return (s,"< I <",S)

print (rect(100,2,7))