x-1/x=1 问x的3次方-1/x的3次放＝？

x^3-(1/x)^3
=[x-(1/x)]*[x^2+x*(1/x)+(1/x)^2]
=[x-(1/x)]*[x^2+1+(1/x)^2]
=[x-(1/x)]*[x^2+(1/x)^2+1]
=[x-(1/x)]*{[x-(1/x)]^2+2+1]
=[x-(1/x)]*{[x-(1/x)]^2+3]
=1*(1^2+3)
=1*4
=4.

x的3次方-1/x的3次放=(x-1/x)(x的2次放+1/x的2次放+1)=(x-1/x)(x的2次放+1/x的2次放-2+3)=(x-1/x)((x-1/x)的2次放+3)=1*(1+3)=4

等于4

x^3-(1/x)^3
=[x-(1/x)]*[x^2+x*(1/x)+(1/x)^2]
=[x-(1/x)]*[x^2+1+(1/x)^2]
=[x-(1/x)]*[x^2+(1/x)^2+1]
=1*4
=4.

x-1/x=1;x^-x-1=0;x=(1/2)(1+ -sqrt(5))

4