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幼苗
共回答了26个问题采纳率:84.6% 举报
(1)由观察知:第2004行式子为20042+(2004×2005)2+20052=(2004×2005+1)2.
(2)第n行式子为n2+[n(n+1)]2+(n+1)2=[n(n+1)+1]2.
理由如下:
n2+[n(n+1)]2+(n+1)2,
=n2+n2(n+1)2+(n+1)2,
=n2[1+(n+1)2]+(n+1)2,
=n2(n2+2n+2)+(n+1)2,
=n4+2n2(n+1)+(n+1)2,
=[n2+(n+1)]2,
=[n(n+1)+1]2.
1年前
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