用python实现牛顿法，求解非线性方程的解

# -*- coding: utf-8 -*-
"""
Created on Sat Nov 13 09:29:27 2021

@author: Machi
"""

import sympy as sp


x = sp.symbols('x')

def f(x):
    
    return x**3 - x

def df_value(x,x_value):
    
    dy = sp.diff(f(x),x)
    
    y_value = float(dy.evalf(
        
    subs={
        
        x: x_value}))
    
    return y_value

def Newton_met(t,error):
    
    i = 1
    
    x_ = t
    
    xn = x_ - f(x_)/df_value(x,x_)
    
    while(abs(xn - x_) > error):
        
        x_ = xn
        
        xn = x_ - f(x_)/df_value(x,x_)
        
        i = i + 1
        
    
    return xn,i

answer = Newton_met(1.5,10**(-8))

print(answer)

(1.0, 6)