-17π/3求他的三角函数值?说明方法

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-17π/3求他的三角函数值?说明方法
-17π/3求他的三角函数值?
说明方法

-17π/3求他的三角函数值?说明方法
sin(-17π/3)
=-sin(17π/3)
=-sin(4π+π+2π/3)
=-sin(π+2π/3)
=-[-sin(2π/3)]
=sin(2π/3)=√3/2;
cos(-17π/3)
=cos(17π/3)
=cos(5π+2π/3)
=cos(4π+π+2π/3)
=cos(π+2π/3)
=-cos(2π/3)
=-1/2.

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