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已知角α的顶点与直角坐标系的原点重合,始边为X轴的正半轴,终边经过点P(-3,4),求sin(2α+2π/3)
人气:144 ℃ 时间:2019-10-09 00:11:58
解答
sina=4/5,cosa=-3/5
sin(2α+2π/3)
=sin2acos2π/3+cos2asin2π/3
=-1/2sin2a+√3/2cos2a
=-sinacosa+√3/2(cos^2a-sin^2a)
=12/25-√3/2*7/25
=(24-7√3)/50
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