> 数学 >
已知x＝
5
+1
2
，求
x3+x+1
x5
的值．
人气：469 ℃　时间：2020-05-07 00:58:11
解答
∵x=
5
+1
2
，
∴
1
x
=
2
5
+1
=
5
-1
2
，
∴1+
1
x
=x，
x3+x+1
x5
=
x2+1+
1
x
x4
=
x2+x
x4
=
x+1
x3
=
1+
1
x
x2
=
x
x2
=
1
x
=
5
-1
2
．
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