设偶函数f(x)对任意x∈R,都有f(x+3)=-1f(x),且当x∈[-3,-2]时,f(x)=4x,则f(107.5)=()A.10B.110C.-10D.-110-数学

题目简介

设偶函数f(x)对任意x∈R,都有f(x+3)=-1f(x),且当x∈[-3,-2]时,f(x)=4x,则f(107.5)=()A.10B.110C.-10D.-110-数学

题目详情

设偶函数f(x)对任意x∈R,都有f(x+3)=-
1
f(x)
,且当x∈[-3,-2]时,f(x)=4x,则f(107.5)=(  )
A.10B.
1
10
C.-10D.-
1
10
题型:单选题难度:中档来源:济南二模

答案

因为f(x+3)=-class="stub"1
f(x)
,故有f(x+6)=-class="stub"1
f(x+3)
=-class="stub"1
-class="stub"1
f(x)
=f(x).函数f(x)是以6为周期的函数.
f(107.5)=f(6×17+5.5)=f(5.5)=-class="stub"1
f(2.5)
=-class="stub"1
f(-2.5)
=-class="stub"1
4×(-2.5)
=class="stub"1
10

故选B

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