若函数f(x)=xcosx,则f/(π2)=______.-数学

题目简介

若函数f(x)=xcosx,则f/(π2)=______.-数学

题目详情

若函数f(x)=xcosx,则f/(
π
2
)
=______.
题型:填空题难度:偏易来源:不详

答案

∵f′(x)=x′cosx+x(cosx)′=cosx-xsinx
f/(class="stub"π
2
)=cosclass="stub"π
2
-class="stub"π
2
sinclass="stub"π
2
=-class="stub"π
2

故答案为-class="stub"π
2

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