已知sin(a+b)等于2/3,sin(a-b0 =1/5
sin(a+b)/sin(a-b)
=(sina*cosb+cosa*sinb)/(sina*cosb-cosa*sinb)
分式上下同除以cosa*cosb
=(tana+tanb)/(tana-tanb)
=(tana/tanb+1)/(tana/tanb-1)
=(2/3)/(1/5)
所以tana/tanb=7/13
☆⌒_⌒☆ 希望可以帮到you~
已知sin(a+b)等于2/3,sin(a-b0 =1/5
sin(a+b)/sin(a-b)
=(sina*cosb+cosa*sinb)/(sina*cosb-cosa*sinb)
分式上下同除以cosa*cosb
=(tana+tanb)/(tana-tanb)
=(tana/tanb+1)/(tana/tanb-1)
=(2/3)/(1/5)
所以tana/tanb=7/13
☆⌒_⌒☆ 希望可以帮到you~