1 - 导入python 模块

import math
from math import cos, tan
from math import *

print(math.sin(1.23))
print(cos(2.34))
print(tanh(1.23))

# 指定别名 as
# 一旦指定了别名，原来的名字就不能用了
import math as mt
print(mt.sin(2))

from math import cos as cs
print(cs(3))

0.9424888019316975

-0.695563326462902

0.8425793256589296

0.9092974268256817

-0.9899924966004454