初二数学题
试说明111···1155···56是一个完全平方数.(其中1有n个,5有n-1个)
参考答案:111```155```56 (有n个1,n-1个5)
=111```1555```5+1
=111```1*(100```0+5)+1
=333```3*333```5+1
=(333```34-1)(333```34+1)+1
=333```34^2-1+1
=333```34^2
试说明111···1155···56是一个完全平方数.(其中1有n个,5有n-1个)
参考答案:111```155```56 (有n个1,n-1个5)
=111```1555```5+1
=111```1*(100```0+5)+1
=333```3*333```5+1
=(333```34-1)(333```34+1)+1
=333```34^2-1+1
=333```34^2