python-3.x - Maclaurin 系列的余弦函数使用 for 循环并在错误差异已经达到我想要的值时停止

Question

你能帮我编写一个 Maclaurin 系列的余弦函数吗？我想消除输入迭代次数。我只是希望它继续运行，直到我达到我想要的精度（在我的代码 0.000000000000001 中）。请简单回答，因为我是 python 的真正初学者。

from math import *
variable_x = float(input("Input for cosine function: "))
number = int(input("Input number of iterations: "))
cosine_x = 0
for number in range (0,number):
    old = cosine_x + (pow(-1, number)*pow(variable_x,2*number)/factorial(2*number))
    print(old)
    if 0 < abs(old - cosine_x) < 0.000000000000001:
        break
    cosine_x = old
print(number)

Result: Input for cosine function: 5 Input number of iterations: 100 1.0 -11.5 14.541666666666668 -7.159722222222221 2.528397817460318 -0.16274663800705413 0.34693981189206935 0.276927936905926 0.28422084055031593 0.283625015089173 0.28366421413266923 0.2836620929723069 0.28366218903935225 0.2836621853444659 0.2836621854666513 0.2836621854631402 0.2836621854632287 0.2836621854632267 0.28366218546322675 18

标签： python-3.x

Answer 1

为避免输入迭代次数，只需使用while循环：

from math import *
variable_x = float(input("Input for cosine function: "))
cosine_x = 0
number = 0
while True:
    old = cosine_x + (pow(-1, number)*pow(variable_x,2*number)/factorial(2*number))
    print(old)
    if 0 < abs(old - cosine_x) < 0.000000000000001:
        break
    cosine_x = old
    number += 1
print(number)