题目内容
利用公式求下列三角函数值:(1)cos(-510°15′); (2)sin(-).
解:(1)cos(-510°15′)= cos510°15′=cos(360°+150°15′)
=cos150°15′=cos(180°-29°45′)=-cos29°45′=-0.868 2.
(2)sin(-)=sin(
-3×2π)=sin
=

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题目内容
利用公式求下列三角函数值:(1)cos(-510°15′); (2)sin(-).
解:(1)cos(-510°15′)= cos510°15′=cos(360°+150°15′)
=cos150°15′=cos(180°-29°45′)=-cos29°45′=-0.868 2.
(2)sin(-)=sin(
-3×2π)=sin
=