求Y=2cos（x+π/4)cos（x-π/4)+√3sin2x的值域和最小正周期

求函数y=7-4sin(x)cos(x)+4cos^2(x)-4cos^4(x)值 求周期 y=2cos（2x- π/4) 函数y=cos(2x+π/4) 求dy y=(cos^2x) 求dy sin(x+y)sin(x-y)=k,求cos^2x-cos^2y Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) y=2cos x (sin x+cos x) y =(cos^2) x - sin (3^x),求y' 求y=cos(π/4-x)的导数 求值域y=3+cos(2x-π/3) 求导数y=cos(2-4x) sin(x+y)cosx+cos(x+y)sinx=1/3 x∈(3π/2,2π) 求cos(2x+π/4) 函数y=cos^2(π/4-x)-cos^2(π/4+x)的值域是 y=cos(x+π/2)+cos的最大值怎么求? 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 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) 求y=（1+cos x)/(sin x+cos x+2)的值域.