用python的库 scipy 解方程组求根

1.标量函数

$x+2cos(x) =0$

程序如下

import numpy as np
from scipy.optimize import root
def func(x):
    return x + 2 * np.cos(x)
sol = root(func, 0.3)
print(sol.x)

结果：[-1.02986653]

2.一组非线性方程

$x_{0}cos(x_{1})=4$ $x_{0}+x_{1}+x_{2}=4$ $x_{1}+x_{2}=2$

程序如下：

import numpy as np
from scipy.optimize import root
def func(x):
    return x[0] * np.cos(x[1]) - 4, \
           x[0] + x[1] + x[2] - 4, \
           x[1] + x[2] - 2
sol = root(func, [1, 2, 1])
print(sol.x)

 结果 ：[-1.97014577  3.16004914  0.82227607]