cos(2x-π/2)=sin 2x
已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x
求导f(x) = cos(3x) * cos(2x) + sin(3x) * sin(2x).
已知函数f(x)=cos(2x-π/3)+sin^2 x-cos^2 x
已知函数f(x)=cos(2x-π\3)+sin²x-cos²x
化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x)
证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4
sin(x+1/2π)=cosx?还是cos-x
已知函数f(x)= [sin(2π-x)sin(π+x)cos(-x-π)] /[2cos(π-x)sin(3π-x)]
化简:2cos2x+2sin^2 x+cos(-x)分之sin2x+sin(π-x)=___________
f(x)=2cos*sin(x+π/3)-^3sin^2x+sinx*cosx
求证(cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2
sin(x+y)sin(x-y)=k,求cos^2x-cos^2y