import math

def f(x):
    return x - math.cos(x)

a = 0
b = 2
n = 10

h = float( b - a ) / n
sum1 = 0.0
sum2 = 0.0
sum3 = 0.0
x = float( a )
for i in range( n ):
    sum1 = sum1 + f( x )
    x = x + h/2
    sum2 = sum2 + f( x )
    x = x + h/2
    sum3 = sum3 + f( x )

print "Riemann sum using left endpoints: ", h * sum1
print "Riemann sum using midpoints: ", h * sum2
print "Riemann sum using right endpoints: ", h * sum3