作业帮cosπ/5 +cos2π/5 +cos3π/5 +cos4π/5 =可以简写.
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/12 19:26:04
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cosπ/5 +cos2π/5 +cos3π/5 +cos4π/5 =可以简写.
cosπ/5 +cos2π/5 +cos3π/5 +cos4π/5 =
可以简写.
cosπ/5 +cos2π/5 +cos3π/5 +cos4π/5 =可以简写.
cos4π/5=-cos(π-4π/5)=-cosπ/5
cos3π/5=-cos(π-3π/5)=-cos2π/5
所以
cosπ/5+cos2π/5+cos3π/5+cos4π/5
=cosπ/5+cos2π/5-cos2π/5-cosπ/5
=0
求COSπ/5*COS2π/5
cosπ/5×cos2π/5=
COSπ/5乘以COS2π/5
cosπ/5×cos2π/5
cosπ/5cos2π/5
cosπ/5cos2π/5=?
cosπ/5 - cos2π/5 怎样变成 cosπ/5 + cos2π/5rt
（cosπ/5）（cos2π/5)的值等于
cosπ/5·cos2π/5等于多少?
cosπ/5*cos2π/5的值等于
cosπ/5 乘以cos2π/5等于多少
化简cosπ/5cos2π/5RT.
若cos(π-θ)=3/5,cos2θ=
cos(π-θ)=3/5 求cos2θ
cos(π- θcos2θ)=3/5 求
cosπ/5 +cos2π/5 +cos3π/5 +cos4π/5 =可以简写.
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