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(sin75度-sin15度)*(cos15度+cos75du)的值
人气:133 ℃ 时间:2020-05-25 03:26:19
解答
令x=75度,y=15度,=sinxcosy+sinxcosx-sinycosy-sinycosx
=sin(x-y)+cos(x+y)=sin60+cos90=根号3/2
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