若1/X+X=3则X^2/(X^4+X^2+1)=^为次方_数学解答

若1/X+X=3
则X^2/(X^4+X^2+1)=
^为次方

人气：410 ℃　时间：2020-01-27 04:26:30

解答

x+1/x=3
平方
x^2+2*x*1/x+1/x^2=9
x^2+2+1/x^2=9
x^2+1/x^2=7
X^2/(X^4+X^2+1)
上下同除以x^2
=1/(x^2+1+1/x^2)
=1/(7+1)
=1/8