Python 函数计算级数部分和：x - x^3/3! + x^5/5! - ...

def series_sum(x, n):
    'Computes the sum of the series s=x-x^3/3!+x^5/5!-x^7/7!+...
    up to n terms for a given value of x
    
    Args:
    x (float): the value of x
    n (int): the number of terms in the series to sum
    
    Returns:
    sum (float): the sum of the series up to n terms
    '
    sum = 0
    sign = 1
    factorial = 1
    for i in range(1, 2*n+1, 2):
        sum += sign * (x**i / factorial)
        sign *= -1
        factorial *= (i+1) * (i+2)
    return sum

# example usage
x = 2
n = 5
print(series_sum(x, n)) # should output 1.1472222222222223