已知m+1m=3,则m4+1m4的值是()A.9B.49C.47D.1-数学

题目简介

已知m+1m=3,则m4+1m4的值是()A.9B.49C.47D.1-数学

题目详情

已知m+
1
m
=3
,则m4+
1
m4
的值是(  )
A.9B.49C.47D.1
题型:单选题难度:偏易来源:不详

答案

∵m+class="stub"1
m
=3,
(m+class="stub"1
m
)2
=32,
∴m2+class="stub"1
m2
=9-2=7,
(m2+class="stub"1
m2
)2
=72,
∴m4+class="stub"1
m4
=49-2=47.
故选C.

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