import sympy
from sympy import oo  #oo表示无穷
import numpy as np
x = sympy.Symbol('x') # S要大写
f = sympy.sin(x)/x
sympy.limit(f,x,oo)


输出结果为 0 
(lim sinx / x)
x--0



import sympy
from sympy import oo  #oo表示无穷
import numpy as np
x = sympy.Symbol('x') # S要大写
f = (x**2-1)/(x-1)
sympy.limit(f,x,1)