sin9°cos15°-sin24°/sin9°sin15°+cos24°的值为___

问题描述:

sin9°cos15°-sin24°/sin9°sin15°+cos24°的值为___

0.3917083927

sin9°cos15°-sin24°/sin9°sin15°+cos24°=sin9°cos15°-sin(9°+15°)/sin9°sin15°+cos(9°+15°)=sin9°cos15°-sin9°cos15°-cos9°sin15°/sin9°sin15°+cos9°cos15°-sin9°sin15°=-cos9°sin15°/c...