已知f(α)=sin(180°-α)sin(270°-α)tan(180°-α)sin(90°+α)tan(180°+α)tan(360°-α),则f(-31π6)的值为______.-高一数学

题目简介

已知f(α)=sin(180°-α)sin(270°-α)tan(180°-α)sin(90°+α)tan(180°+α)tan(360°-α),则f(-31π6)的值为______.-高一数学

题目详情

已知f(α)=
sin(180°-α)sin(270°-α)tan(180°-α)
sin(90°+α)tan(180°+α)tan(360°-α)
,则f(-
31π
6
)的值为______.
题型:填空题难度:偏易来源:不详

答案

由题意得:f(α)=
sinα(-cosα)(-tanα)
cosαtanα(-tanα)
=-cosα,
则f(-class="stub"31π
6
)=-cos(-class="stub"31π
6
)=-cos(5π+class="stub"π
6
)=-cos(π+class="stub"π
6
)=cosclass="stub"π
6
=
3
2

故答案为:
3
2

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