来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/05/17 01:47:45
公式忘记了,
sin(30°-C)=sin(30°)cosC-cos(30°)sinC=(cosC-√3sinC)/2
sin(30°+C)=sin(30°)cosC+cos(30°)sinC=(cosC+√3sinC)/2
cos(30°-C)=cos(30°)cosC+sin(30°)sinC=(√3cosC+sinC)/2
cos(30°+C)=cos(30°)cosC-sin(30°)sinC=(√3cosC-sinC)/2
作业帮