python求s =1×2-2×3+3×4-4×5+ …+(-1) (n-1) ×n×(n+1)

路城楠大帅哥的python

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开发时间:2022/3/27 17:49

-- coding: UTF-8 --

i = 1 ; t = 0; sum = 0;n=int(input())
while i <=n:
t=(-1)**(i-1)i(i+1)#表达式计算

sum = sum + t
i += 1

print(sum)