3. 已知實數a(a=0.12457…)的小數點後第n位的數字等於n x (2)^(1/2)的整數部分之首位數的數字。試證a是一個無理數。 (六分)
2006-11-06 10:00
isomorphism Not too shy to talk
註冊日: 2007-01-30 發表數: 40
Re: 環球城市數學競賽2006秋季賽高中組高級卷第3題
Hint: Assume to the contrary that 'a' is periodic. Then consider certain terms of 'a' and derive a contradiction.
2007-02-02 20:55
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