用Python计算函数f(x)

这个应该怎么写？刚开始学Python，语法不会。话说为什么非要30个字符才能发表？

import math
x = float(input())
y = math.sin(math.radians(35))+(math.ex-15*x)/((x4+1)*0.5)-math.log(7x, math.e)
print('{:.3f}'.format(y))

import math

x = float(input())
y = math.sin(math.radians(35))+(math.e**x-15*x)/((x**4+1)**0.5)-math.log(7*x, math.e)
print('{:.3f}'.format(y))

import math

x = float(input())
y = math.sin(math.radians(35))+(math.ex-15*x)/(math.sqrt(x4+1))-math.log(7*x, math.e)
print('f({:,})={:.3f}'.format(x,y))