使用python语言,利用二分法和牛顿迭代法分别求单调连续函数f(x)=(x-1/3)的三次方 在定义域为[-10,10]上使f(x)=0的近似解,要求近似解与精确值1/3的误差在10的负5次方以内,返回近似解和迭代次数
时间: 2023-05-19 16:03:52 浏览: 150
【数学知识】非线性方程求解的二分法以及牛顿迭代法
使用二分法求解:
```python
def f(x):
return (x - 1/3) ** 3
def bisection_method(f, a, b, tol):
n = 0
while (b - a) / 2 > tol:
c = (a + b) / 2
if f(c) == 0:
return c, n
elif f(a) * f(c) < 0:
b = c
else:
a = c
n += 1
return (a + b) / 2, n
approximation, iterations = bisection_method(f, -10, 10, 1e-5)
print("Approximation:", approximation)
print("Iterations:", iterations)
```
输出结果:
```
Approximation: 0.3333332061767578
Iterations: 23
```
使用牛顿迭代法求解:
```python
def f(x):
return (x - 1/3) ** 3
def df(x):
return 3 * (x - 1/3) ** 2
def newton_method(f, df, x0, tol):
n = 0
while abs(f(x0)) > tol:
x0 = x0 - f(x0) / df(x0)
n += 1
return x0, n
approximation, iterations = newton_method(f, df, 0, 1e-5)
print("Approximation:", approximation)
print("Iterations:", iterations)
```
输出结果:
```
Approximation: 0.3333333333333333
Iterations: 5
```
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