cos(-1200°)=______.-数学

题目简介

cos(-1200°)=______.-数学

题目详情

cos(-1200°)=______.
题型:填空题难度:中档来源:不详

答案

cos(-1200°)=cos1200°
=cos(3×360°+120°)
=cos120°=cos(180°-60°)
=-cos60°=-class="stub"1
2

故答案为:-class="stub"1
2

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