已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值

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已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值

已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值
已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值

已知x/(xx+x+1)=a,求xx/(xxxx+xx+1)的值
x/(xx+x+1)=a分子分母除以x,
1/(x+1+1/x)=a,
x+1/x=1/a -1,两边平方
xx +2+ 1/xx=(1/a-1)^2
xx+ 1/xx=(1/a-1)^2-2
xx/(xxxx+xx+1)分子分母除以xx
=1/(xx+1/xx+1)
=1/〔(1/a-1)^2-2+1〕
=1/〔(1/a-1)^2-1〕
=a^2/(1-2a) .