from math import pi
cdef extern from "math.h":
double sin(double)
cdef double f(double x) except *:
return sin(x**2)
def integrate_f(double a, double b, int N):
cdef int i
cdef double s, dx
s = 0
dx = (b-a)/N
for i in range(N):
s += f(a+i*dx)
return s * dx