已知x/x2+x−1=1/9,则x2x4+x2+1=_.

问题描述:

已知

x
x2+x−1
=
1
9
,则
x2
x4+x2+1
=______.

x
x2+x−1
=
1
x−
1
x
+1
=
1
9

∴x-
1
x
=8,
两边平方得:x2+
1
x2
-2=8,即x2+
1
x2
=10,
则原式=
1
x2+
1
x2
+1
=
1
11

故答案为:
1
11