已知x+1x=3,那么x4+1x4=______.-数学

题目简介

已知x+1x=3,那么x4+1x4=______.-数学

题目详情

已知x+
1
x
=3,那么x4+
1
x4
=______.
题型:填空题难度:偏易来源:不详

答案

∵x+class="stub"1
x
=3,
∴x2+class="stub"1
x2
=(x+class="stub"1
x
)2-2=7,
x4+class="stub"1
x4
=(x2+class="stub"1
x2
)2-2=47.

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