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标题: [数学] 2007-10-27 初一 [打印本页]

作者: 老猫    时间: 2007-10-27 07:04     标题: 2007-10-27 初一

试证数列49,4489,444889,…的每一项都是完全平方数。.
作者: duyan    时间: 2007-10-27 09:10

66...67^2=(66...66+1)^2=66...66^2+2*66...66+1
=44...4355...56+133...32+1=44...488..9
所以,66...67^2=44...488..9.




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