化简y=(2cos^4x-3cos^2x+1)/cos2x

化简y=(2cos^4x-3cos^2x+1)/cos2x 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) 2cos(x+y)cosx-cos(2x+y)化简 y=2cos x (sin x+cos x) 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) Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 证明cos 2x cos x=1/2(cos x+cos 3x) 化简：Y=cos^X＋根号3倍的sinXcosX是COS^2x y=sinxcosx+cos(2x)化简 y=(cos x-2)/(cos x-1)的值域 y=cos^2 x-cos x +1的值域y=cos^2 x+cos x +1的值域, 求函数y=7-4sin(x)cos(x)+4cos^2(x)-4cos^4(x)值 y=(sin x + COS x)^2 y =(cos^2) x - sin (3^x),求y' y=cos(π/3-x)cos[π/2（x-1)]判断奇偶性y=cos(π/3-x)cos(π/3+x)判断奇偶性 y=4√2sin x cos x+cos 2x 的值域是 【高中数学】已知cos(x+y)=1/3,cos(x-y)=2/3,且0