sin(a+b)=sinacosb+sinbcosa=2/3sin(a-b)=sinacosb-sinbcosa=1/5可得:sinacosb=13/30,sinbcosa=7/30所以sinacosb/sinbcosa...上下同时除以cosacosb=tana/tanb=13/7泪笑为您解答,请点击右上角[满意];如若您有不满意之...