sin(x-y)sin(x+y)-cos(x-y)cos(x+y)

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=(sin x + COS x)^2 化简sin(2x-y)*sin y+cos(2x-y)*sin y 请问sin（x+y）cos y-cos（x+y）sin y得多少 sin(x+y)sin(x-y)=k,求cos^2x-cos^2y 化简sin (x+y)sin x +cos (x+y)cos x= y=2cos x (sin x+cos x) 解微分方程：y` cos y =(1+cos x sin y)sin y. 参数方程x=cos(sin+cos)y=sin（cos+sin）化为普通方程 求微分方程y'cos y+ sin(x-y)=sin(x+y)的通解. 求解微分方程y'*cos(y)=x+1-sin(y) 化简sin(x+y)sinx+cos(x+y)cosx 化简sin(x+y)sinx+cos(x+y)cosx等于? 化简cos(x+y)sinx-sin(x+y)cosx sin(2x+y)/sinx-2cos(x+y) 化简 化简cos(x+y)sinx-sin(x+y)cosx