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计算cos(负三分之十六派)

题目详情
计算cos(负三分之十六派)
▼优质解答
答案和解析
cos(-16π/3)
=cos(16π/3)
=cos[(18-2)π/3]
=cos(6π-2π/3)
=cos(-2π/3)
=cos(2π/3)
=cos(π-π/3)
=-cos(π/3)
=-1/2