请问sin（x+y）cos y-cos（x+y）sin y得多少

请问sin（x+y）cos y-cos（x+y）sin y得多少 证明COS（X+Y）COS（X-Y）=COS^2X-SIN^2Y 参数方程x=cos(sin+cos)y=sin（cos+sin）化为普通方程 cos（x+y）sinx-sin（x+y）cosx 化简sin(x+y)sin(x-y)-cos(x+y)cos(x-y)的结果是? 化简sin(x+y)cos(x-y)+cos(x+y)sin(x-y) sin(x-y)sin(x+y)-cos(x-y)cos(x+y) y=2cos x (sin x+cos x) 证明cos(x+y)cos(x-y)= cos^2(x)-sin^2(y) 请问怎么证明sinX+sin(X+Y)+sin(X+2Y)/cosX+cos(X+Y)+cos(X+2Y)=tan(X+Y), y=(sin x + COS x)^2 当cos^2x-cos^2y=√3/2时,求sin(x+y）×sin(x-y) 解微分方程：y` cos y =(1+cos x sin y)sin y. sin(x+y)sin(x-y)=k,求cos^2x-cos^2y cos(x+y)*cos(x-y)=cos*cosx+sin*siny 化简sin (x+y)sin x +cos (x+y)cos x= 函数y=cos（sin x）的值域为? 请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2)