Sorry, 答案应该是2.22580645161

回答: 不让贴公式hoho3652014-09-16 17:12:29

#Python code:

a = 0.69
b = 1 - a

average = 0
left = 1.0
i = 0

while i average += i * b * left
left = left * a
i = i + 1

print average

所有跟帖: 

请看我上面的无限次答案:0.69/0.31=2.225806452 -jinjing- 给 jinjing 发送悄悄话 (22 bytes) () 09/17/2014 postreply 10:20:27

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