一个关于python的问题

Question

定义函数cos（x）定义为 f(x，n)怎么保留5位小数。和求和问题

Answer 1

如有帮助给个采纳谢谢 , 公式如下 :
$$ \cos(x) = \frac{x^{0}}{0!}−\frac{x^{2}}{2!} + \frac{x^{4}}{4!}−\frac{x^{6}}{6!} + ... $$

代码如下:

import math

def f(x, n):
    result = 0.0
    term = 1.0
    factorial = 1.0
    sign = 1

    k = 0
    while abs(term) >= n:
        result += term
        k += 1
        factorial *= (2 * k - 1) * (2 * k)
        term = math.pow(x, 2 * k) / factorial * sign
        sign *= -1

    return round(result, 5)

# 测试代码
x = -4.2
n1 = 0.0001
n2 = 0.01

result1 = f(x, n1)
result2 = f(x, n2)

print(f"当x={x}，n={n1}时，cos(x)的近似值为：{result1}")
print(f"当x={x}，n={n2}时，cos(x)的近似值为：{result2}")