公式不便于在这里编辑，所以在word中编辑好了，截图过来。
用python+牛顿迭代法 求 y =（x-2）**3的解
import numpy as np
import matplotlib.pyplot as plt
‘‘‘
牛顿迭代法实现 y =（x-2）**3的解
‘‘‘
def f(x):
return (x-2)**3
def fd(x):
return 3*((x-2)**2)
def newtonMethod(n,assum):
time = n
x = assum
next = 0
a = f(x)
b = fd(x)
print(‘a = ‘+str(a)+‘,b = ‘+str(b)+‘,time = ‘+str(time))
if f(x) == 0.0:
return time,x
else:
next = x-a/b
print(‘next x = ‘+str(next))
if a - f(next)<1e-6:
print(‘meet f(x) = 0 , x = ‘+ str(next)) ##设置跳出条件，同时输出满足f(x) = 0 的x的值
else:
return newtonMethod(n+1,next)
newtonMethod(0,4.0)
C:\ProgramData\Anaconda3\python.exe D:/python/TensorFlow/算法实例/牛顿迭代法.py a = 8.0,b = 12.0,time = 0 next x = 3.3333333333333335 a = 2.370370370370371,b = 5.333333333333334,time = 1 next x = 2.888888888888889 a = 0.7023319615912207,b = 2.3703703703703702,time = 2 next x = 2.5925925925925926 a = 0.20809835898999132,b = 1.0534979423868311,time = 3 next x = 2.3950617283950617 a = 0.0616587730340715,b = 0.4682213077274805,time = 4 next x = 2.263374485596708 a = 0.018269266084169365,b = 0.20809835898999157,time = 5 next x = 2.1755829903978054 a = 0.005413115876790937,b = 0.09248815955110752,time = 6 next x = 2.11705532693187 a = 0.001603886185715827,b = 0.04110584868938101,time = 7 next x = 2.078036884621247 a = 0.0004752255365083959,b = 0.01826926608416941,time = 8 next x = 2.052024589747498 a = 0.00014080756637285685,b = 0.008119673815186359,time = 9 next x = 2.034683059831665 a = 4.17207604067724e-05,b = 0.0036087439178606037,time = 10 next x = 2.023122039887777 a = 1.2361706787192059e-05,b = 0.0016038861857158443,time = 11 next x = 2.015414693258518 a = 3.662727936945795e-06,b = 0.0007128383047625975,time = 12 next x = 2.0102764621723455 a = 1.0852527220580603e-06,b = 0.00031681702433894134,time = 13 next x = 2.0068509747815635 meet f(x) = 0 , x = 2.0068509747815635 Process finished with exit code 0
从运行的结果可以看出近似根x = 2.0068509747815635
原文地址：https://www.cnblogs.com/liuhuacai/p/11774447.html
时间： 2024-11-02 18:58:50