已知0已知0已知0= =平方2找半天了·············sinα=4/5cos(a+b)=12/1363²+16²=65²b=(a+b)-acosb=cos[(a+b)-a]=cos(a+b)*cosa-sin(a+b)*sina=16/65sinb=63/65tanb=63/16
已知0= =平方2找半天了·············sinα=4/5cos(a+b)=12/1363²+16²=65²b=(a+b)-acosb=cos[(a+b)-a]=cos(a+b)*cosa-sin(a+b)*sina=16/65sinb=63/65tanb=63/16