cos73°cos13°+cos17°sin13°=求答案

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cos73°cos13°+cos17°sin13°=求答案cos73°cos13°+cos17°sin13°=求答案cos73°cos13°+cos17°sin13°=求答案cos73°cos13°+

cos73°cos13°+cos17°sin13°=求答案
cos73°cos13°+cos17°sin13°=求答案

cos73°cos13°+cos17°sin13°=求答案
cos73°cos13°+cos17°sin13°
=sin17°cos13°+cos17°sin13°
=sin(17°+13°)
=sin30°
=1/2

cos73°cos13°+cos17°sin13°
=cos(73°-13°)
=cos60°
=1/2

cos73°cos13°+cos17°sin13°=sin17°cos13°+cos17°sin13°=sin(17°+13°)=sin30°=1/2