sinx-siny=-√3/3 cosx-cosy=-1/3 则cos(x-y)

来源：学生作业帮助网编辑：六六作业网时间：2024/07/02 18:15:48

sinx-siny=-√3/3cosx-cosy=-1/3则cos(x-y)sinx-siny=-√3/3cosx-cosy=-1/3则cos(x-y)sinx-siny=-√3/3cosx-cosy

sinx-siny=-√3/3 cosx-cosy=-1/3 则cos(x-y)
sinx-siny=-√3/3 cosx-cosy=-1/3 则cos(x-y)

sinx-siny=-√3/3 cosx-cosy=-1/3 则cos(x-y)
sinx-siny=-√3/3
两边同时平方得：
sin²x-2sinxsiny+sin²y=1/3 ①
cosx-cosy=-1/3
两边同时平方得：
cos²x-2cosxcosy+cos²y=1/9 ②
由①+②得：
-2sinxsiny-2cosxcosy=4/9
即-2(sinxsiny+cosxcosy)=4/9
-2cos(x-y)=4/9
cos(x-y)=-2/9
答案：-2/9

sinx+siny=1/3,则siny-(cosx)^2的最大值为?最小值为? 已知sinx+siny=1/3求siny-(cosx)^2的最小值和最大值已知sinx+siny=1/3求siny-(cosx)^2的最小值已知sinx+siny=2/3cosx+cosy=2/3,则sinx+cosx的值? 已知sinx+siny=√2,cosx+cosy=2√3/3,求tanx*tany sinx-siny=-√3/3 cosx-cosy=-1/3 则cos(x-y) 已知sinx+siny=1/3,sinx-siny的最小值已知sinx+siny=1/3,sinx-已知sinx+siny=1/3,sinx-siny的最小值是求y=(sinx)^2-cosx+2最值已知sinx+siny=1/3,求siny-(cosx)^2的最值 cosx+cosy=1/2sinx+siny=√3/3,则cos(x-y)的值为 sinx-siny=1/3,cosx-cosy=2/3,sin(x+y)=? cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)=? cosx-cosy=1/2,sinx-siny=1/3,sin(x+y)=RT 已知cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)= sinx+cosy=1/3 cosx+siny=1/6 则sin(x+y)=?RT 若cosx*cosy+sinx*siny=1/3 ,则cos(2x-2y)=? 已知cosx+cosy=1/2,sinx-siny=1/3,求cos(x+y) cosx-cosy=4/1,sinx-siny=3/1求cos(x-y) sinx+cosy=1/3 cosx+siny=1/6 则 sin(x+y)?