y'=4sin(2x+π/3)cos(2x+π/3) 化简 y'=2sin(4x+2π/3).怎么化简的?

Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) y=2cos(x/4+ π/3)-3sin(x- π/4)y=sin(4x- π/3)-cos(3x+π/2) y =(cos^2) x - sin (3^x),求y' y=(sin x + COS x)^2 已知sinx=3/5,x∈(π/2,π),求【sin(x+y)+sin(x-y)】/【cos（x+y）+cos（x-y）】的值 y=2cos x (sin x+cos x) 求函数y=cos(9/2π+x)+sin^2x的最大值和最小值还有一题 已知sinx+cosx=1/2,求sin^3x+cos^3x和sin^4x+cos^2x y=sin(2x-π/4)+cos(3x+π/3)的导数 当cos^2x-cos^2y=√3/2时,求sin(x+y）×sin(x-y) sin(x+y)sin(x-y)=k,求cos^2x-cos^2y 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) 已知sinθ+cosθ=2sinx,sinθcosθ=sin²y,求证：4cos²2x=cos²2y cos(x-y/2)=-1/9,sin(x/2-y)=2/3,π/2 1.y=sin(-X+π/6)2.y=cos(-2X+π/3) sin(x+y)cosx+cos(x+y)sinx=1/3 x∈(3π/2,2π) 求cos(2x+π/4) 函数y=cos^4x-sin^4x的最小正周期y=(cos^2x+sin^2x)(cos^2x-sin^2x)为什么等于cos^2x-sin^2x=cos2x谢谢