怎么实现前一项分母落在下一项分子

你好，同学，考虑斐波拉契数列和交错乘除

def sfun(x,n):
    a = 1.
    b = 1.
    s = 0.
    for i in range(n):
        c = a+b
        if(i%2==0):
            s = s + b/(c*x)
        else:
            s = s - b*x/c
        a = b
        b = c
    return s
x = 6.66
n = int(input("输入n："))
sfun(x,n)

结果展示

答题不易有帮助望给个采纳支持答主哦

你用一个变量记录一下，下一次循环时先赋值给分子