已知x平方-x-1=0,则x四次方+2x+1/x五次方=
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2011-08-21 · 知道合伙人教育行家
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x^2-x-1=0
x^2=x+1
x^4=(x^2)^2 = (x+1)^2 = x^2+2x+1=x+1+2x+1=3x+2
x^5=x * x^4 = x(3x+2) = 3x^2+2x = 3(x+1)+2x = 5x+3
(x^4 + 2x + 1) / x^5 = (3x+2+2x+1)/(5x+3) = (5x+3)/(5x+3) =1
x^2=x+1
x^4=(x^2)^2 = (x+1)^2 = x^2+2x+1=x+1+2x+1=3x+2
x^5=x * x^4 = x(3x+2) = 3x^2+2x = 3(x+1)+2x = 5x+3
(x^4 + 2x + 1) / x^5 = (3x+2+2x+1)/(5x+3) = (5x+3)/(5x+3) =1
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x²=x+1
平方
x^4=x²+2x+1=(x+1)+2x+1=3x+2
x^5=x^4*x=x(3x+2)=3x²+2x=3(x+1)+2x=5x+3
所以原式=(3x+2+2x+1)/(5x+3)=(5x+3)/(5x+3)=1
平方
x^4=x²+2x+1=(x+1)+2x+1=3x+2
x^5=x^4*x=x(3x+2)=3x²+2x=3(x+1)+2x=5x+3
所以原式=(3x+2+2x+1)/(5x+3)=(5x+3)/(5x+3)=1
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