cos(x) with approximation

cos.py

#cos(x) approximation

def fak (x):
	if x == 0:
		return 1
	else:
		return x * fak(x-1)

import math	
i = 2
t = math.pi / 3.0
result1 = 0.0
channel = 0.0

while i < 180:
	#when i > 170, return an error like this 
	#OverflowError: long int too large to convert to float
	if math.fmod( i / 2, 2 ) == 0:
		channel = math.pow(t,i) / fak(i)
	else:
		channel = math.pow(t,i) / fak(i) * -1
	result1 += channel
	print i
	i = i + 2

	

print "Result 1 : {0} " . format(1-result1)