sin(a+b)=1/2,sin(a-b)=1/3,则tana/tanb=?
sin(a+b)=sinacosb+cosasinb=1/2
sin(a-b)=sinacosb-cosasinb=1/3
联立--->sinacosb=5/12,cosasinb=1/12
相除--->tana/tanb=5