2cos^4x-2cos^2x+1/2除以2tan(派/4-x)sin^2(派/4+x)怎么化简

cos x>-1/2 证明cos 2x cos x=1/2(cos x+cos 3x) 2cos x (sin x -cos x)+1 求解三角函数 cos 2 X (1 - 2 sin ^2 2 X) + cos 4 X ( 1 + cos 2 X)cos 2 X (1 - 2 sin ^2 2 X) + cos 4 X ( 1 + cos 2 X) = cos 2 X cos4X (1 + cos 2 X) = cos 4 X (1 +2cos 2X) = 0 化简cos 2x (cos(x))^-2导数 cos(x^2)dx 2（cos x）^2=1+cos 2x, 2cos^2x等于cos^4x么? y=(cos x-2)/(cos x-1)的值域 cos 2x(1-2sin^2 2x) + cos 4x (1+cos 2x)= Cos x=-1/2 y=cos^2 x-cos x +1的值域y=cos^2 x+cos x +1的值域, 如何求 lim(n→∞)cos(x/2)cos(x/4)...cos(x/2n) 化简f(x)=cos(-x/2)+cos(4k+1/2-x/2) 化简1+sin x/cos x·sin2x/2cos²（π/4-x/2） 若sinx+sin^2x=1,则cos^2x+cos^4x=? y=2cos x (sin x+cos x)