sinx+siny=1/4,cosx+cosy=1/3求tan(x-y)
sinx+siny=1/4,cosx+cosy=1/3求tan(x-y)
设sinX+sinY=1/4,cosX+cosY=1/3,求tan(X+Y)的值.要详解.
sinx+siny=1/3 ,cosx+cosy=1/2,求tan(x+y)的值.
cosx-cosy=4/1,sinx-siny=3/1求cos(x-y)
已知cosx+cosy=1/2,sinx-siny=1/3,求cos(x+y)
sinx+siny=-1/3 cosx+cosy=1/2,求sin(x+y)的值.
sinx+siny=3/5,cosx+cosy=4/5,求cos(x-y)
已知sinx+siny=1/3,cosx-cosy=1/5,求cos(x+y),sin(x-y).
1,已知sinx+siny=1/4,cosx+cosy=1/3 tan(x+y)=?2,体积为72的正四面体,连接两个面
cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)=?
若cosx*cosy+sinx*siny=1/3 ,则cos(2x-2y)=?
设cosX+cosY=1/2,sinX+sinY =1/4,求cos(X-Y)的值