Is there a semantic error in my code that I'm missing?

Question

I made a code to try and compute the partial sum of a series, but it keeps producing a result that's about 0.01 off. It looks pretty straightforward to me and I haven't been able to spot what my mistake might've been, but there's definitely something off.

import math
def f(n):
    s = 0
    for x in range(1,n+1):
        y = x*(4**x)
        d = (math.factorial(x))*(4**x)
        n = -1**x
        s += n/d
    print(s)

f(7)

`-1**x` is always `-1`, due to the order of operations - you probably want `(-1)**x`. What was the point of calculating `y`, since you don't use it anywhere? — jasonharper, Nov 08 '22 at 15:18
I disagree to say that this question is a duplicate. Correcting the pow call does not seem to be the solution. — , Nov 08 '22 at 16:04

score 1 · Answer 1 · 2022-11-08T16:05:38.927

1

As written, your function computes a good approximation of - (√√e - 1) ~ -0.28402541668774148407342056806244.

By applying the fix suggested by jason, the constant is 1/√√e - 1 ~ -0.22119921692859513175482973302168.

The discrepancy is larger than 0.01. Given the abnormal assignment to y, we can suspect that you didn't post the right code.

edited Nov 08 '22 at 16:05

answered Nov 08 '22 at 15:38

Is there a semantic error in my code that I'm missing?

1 Answers1