求值(sin9°cos15°-sin24°)/(sin9°sin15°+cos24°)
人气:285 ℃ 时间:2020-05-13 23:01:28
解答
sin24=sin9cos15+cos9sin15
cos24=cos9cos15-sin9sin15
原式等于-cos9sin15/cos9cos15=-tan15
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