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cos11π∕6等于多少啊?

题目详情
cos11π∕6 等于多少啊?
▼优质解答
答案和解析
cos(11π/6)
=cos(12π/6-π/6)
=cos(2π-π/6)
=cos(-π/6+2π)
=cos(-π/6)
=cos(π/6)
=cos30°
=1/2