化简COS8°-SIN17°SIN9°/COS9°

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/30 05:45:24
化简COS8°-SIN17°SIN9°/COS9°

化简COS8°-SIN17°SIN9°/COS9°
化简COS8°-SIN17°SIN9°/COS9°

化简COS8°-SIN17°SIN9°/COS9°
cos8°=cos(17°-9°)=cos17°cos9°+sin17°sin9°
则:
原式=[cos17°cos9°]/[cos9°]=cos17°