左右为难0516
幼苗
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∵α是第二象限角,sinα=3/5
∴cosα=-√[1-(sinα)^2]=-4/5
故sin(37π/6-2α)=sin(6π+π/6-2α)
=sin(π/6-2α)
=sin(π/6)cos(2α)-cos(π/6)sin(2α)
=(1/2)((cosα)^2-(sinα)^2)-(√3/2)(2sinαcosα)
=(1/2)((-4/5)^2-(3/5)^2)-(√3/2)(2(3/5)(-4/5))
=(7+24√3)/50.
1年前
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