Question

牛顿的方法是连续找到更接近多项式根的近似值我学会了找平方根：

    from sys import argv
    script, k,epsilon  = argv

    def find_square_root(k, epsilon):
        guess = k/2
        while abs(guess**2 -k) >= epsilon:
            guess = guess - (guess**2 -k)/(2*guess)
            print(f"Square root of {k} is about {guess}.")

    k = float(argv[1])
    epsilion = float(argv[2])
    find_square_root(k, epsilion)

运行它并来：

    $ python3 successive_approximation.py 128 0.001
    Square root of 128.0 is about 33.0.
    Square root of 128.0 is about 18.439393939393938.
    Square root of 128.0 is about 12.690526879310774.Square root of 128.0 is about 11.388395266147043.
    Square root of 128.0 is about 11.31395340237364.
    Square root of 128.0 is about 11.313708501635368.

如何使用Newton的方法查找多维数据集根目录？

Answer 1

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def find_cube_root(k, epsilon):
  guess = k
  while(((1/3)*(2*guess + k/guess**2))**3 - k >= epsilon):
    guess = (1/3)*(2*guess + k/guess**2)
    print(f"Cube root of {k} is about {guess}.")

find_cube_root(100, .001)

输出：

Cube root of 100 is about 66.66999999999999.
Cube root of 100 is about 44.4541659167229.
Cube root of 100 is about 29.65297823132699.
Cube root of 100 is about 19.806561134963502.
Cube root of 100 is about 13.28934310575367.
Cube root of 100 is about 9.048305445603736.
Cube root of 100 is about 6.4393440686740675.
Cube root of 100 is about 5.096783929887992.
Cube root of 100 is about 4.6810321649028035.
Cube root of 100 is about 4.641920257658932.

用牛顿法找到一个立方根

1 个答案: