cos 2x -(cos 2x)^3怎么算出(sin 2x)^2 *cos 2x

证明cos 2x cos x=1/2(cos x+cos 3x) cos 2x -(cos 2x)^3怎么算出(sin 2x)^2 *cos 2x 2cos(x/2)(3^(1/2)sin(x/2)-cos(x/2))怎么化简? (sin^2x+cos^2x )(sin^2x-cos^2x)怎么得sin^2x-cos^2x? cos（x-2派/3)=-cos(x+派/3) 求不定积分cos(3x)cos(2x) sin x 3 cos x =2怎么解? cos(3x/2)cos(x/2)-sin(3x/2)sin(x/2)=cos(3x/2+x/2)=cos2x 怎么得出这个结果的? 化简cos 2x (cos(x))^-2导数 cos(x^2)dx cos x>-1/2 cos3x/2cosx/2怎么换成cos(x+x/2).cos(x-x/2) 怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2 cos^2 x 的导数怎么求? sin2x-2cos平方x 怎么化简类? 1/（cos x）^2怎么积分, ∫cos^2 x dx怎么解?