邪恶魔人 扎克怎么样:数学题目

来源:百度文库 编辑:高校问答 时间:2024/04/27 20:32:12
sin(a+b)=0.5
sin(a-b)=0.1 求tana/tanb

sin(a+b)=sina*cosb+cosa*sinb=0.5
sin(a-b)=sina*cosb-cosa*sinb=0.1
cosa*sinb=-0.2,sina*cosb=0.3
cosa*sinb/(sina*cosb)=-2/3
ctana*tanb=-2/3
tana/tanb=-3/2

应该这样:sin(a+b)=sina*cosb+cosa*sinb=0.5
sin(a-b)=sina*cosb-cosa*sinb=0.1
cosa*sinb=-0.2,sina*cosb=0.3
cosa*sinb/(sina*cosb)=-2/3
ctana*tanb=-2/3
tana/tanb=-3/2