■ドミノ被覆・畳被覆(その26)

 

△n(x)=Π(x−2cos(kπ/(n+1))と因数分解されて

2cos(kπ/(n+1))を零点にもつことがわかる.

△n(3)=F2n+2

△n-1(3)=F2n

△n-1(3)=Π(3−2cos(kπ/n))=F2n

nが偶数のとき

△n/2-1(3)=Π(3−2cos(2kπ/n))=Fn

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Fn=Zn-1(1)

=Π(1−2icos(kπ/n))

=Π(1+4cos^2(kπ/n))

=Π(3+2cos(2kπ/n))

Fn=Π(1+4cos^2(kπ/n),k=1〜[n/2]

と比較されたい.

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