已知sinx+siny+sinz=cosx+cosy+cosz=0,求tan(x+y+z)+tanxtanytanz的值
已知sinx+siny+sinz=cosx+cosy+cosz=0,求tan(x+y+z)+tanxtanytanz的值
sinx+siny+sinz=0,cosx+cosy+cosz=0,求cos(y-z)的值.
已知x,y,z均为锐角,且sinx+sinz=siny,cosx-cosz=cosy,求x-y的值.
sinx+siny+sinz=0;cosx+cosy+cosz=0;求cos(x-y)
已知sinx+siny+sinz=0,cosx+cosy+cosz=0 则cos(x-y)=______ 要详解
已知sinx+siny+sinz=0,cosx+cosy+cosz=0,求证cos(x-y)=cos(y-z)=cos(
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.
sinx+siny=1/4,cosx+cosy=1/3求tan(x-y)
sinx+siny=-1/3 cosx+cosy=1/2,求sin(x+y)的值.
已知sinx+siny=(√2)/4,cosx+cosy=1/2,求cos(x-y)的值.
已知sinx-siny=-2/3,cosx-cosy=2/3,且x.y为锐角,则tan(x-y)的值为?