根据题意
韦达定理
tana+tanb=-(4m+2)
tana*tanb=2m
sin(a+b)/cos(a-b)=(sinacosb+cosasinb)/(cosacosb+sinasinb)
=(tana+tanb)/(1+tanatanb)
=(-4m-2)/(1+2m)
=-2(1+2m)/(1+2m)
=-2
根据题意
韦达定理
tana+tanb=-(4m+2)
tana*tanb=2m
sin(a+b)/cos(a-b)=(sinacosb+cosasinb)/(cosacosb+sinasinb)
=(tana+tanb)/(1+tanatanb)
=(-4m-2)/(1+2m)
=-2(1+2m)/(1+2m)
=-2