y=sin(x/2)-cos(x/2)求周期T?

sin(x+y)sin(x-y)=k,求cos^2x-cos^2y y =(cos^2) x - sin (3^x),求y' Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 求y=sin x/(2-cos x)值域 y=(sin x + COS x)^2 y=2cos x (sin x+cos x) 当cos^2x-cos^2y=√3/2时,求sin(x+y）×sin(x-y) 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 已知函数y=(sin x+ cos x)(sin x+cos x)+2cos x*cos x ,求它的递减区间语气亲和、态度友好 求y=（1+cos x)/(sin x+cos x+2)的值域. 化简y=sin^2 x + cos 2x 求周期sin^2 x 是平方 y=1-sin(2x)/sin(x)-cos(x)求T.最值 求函数y =cos 2x +sin 2x /cos 2x -sin 2x 的最小正周期 求y=sin＾2(x)+3sin(x)cos(x)-2cos＾2(x)的最大值 求y=sin x +2sin x cos x -3cos²x 的周期和值域, 求函数y=7-4sin(x)cos(x)+4cos^2(x)-4cos^4(x)值 证明COS（X+Y）COS（X-Y）=COS^2X-SIN^2Y 证明cos(x+y)cos(x-y)= cos^2(x)-sin^2(y)