已知0已知0
已知0因为0<α<π,tanα=-2,所以sinα=2根号5/5,cosα=-根号5/5sin(α+π6)=sinαcosπ/6+cosαsinπ/6=2根号5/5根号3/2+(-根号5/5)×1/2=2根号15-根号5/10