Python3 数字Number Cos Function

#!/usr/bin/python3
import math

print ("cos(3) : ",  math.cos(3))
print ("cos(-3) : ",  math.cos(-3))
print ("cos(0) : ",  math.cos(0))
print ("cos(math.pi) : ",  math.cos(math.pi))
print ("cos(2*math.pi) : ",  math.cos(2*math.pi))