sin(-3x)=?cos(-3x)=?tan(-3x)=?请详细说明理由

已知sin(x)+3cos(x)=2,求sin(x)-cos(x)/sin(x)+cos(x)=? 2sin^2x - 5sin x cos x=3 cos^2x,求X, 若cos x-sin x = 0.5,则cos^3 x-sin^3 x = 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 cos x sin x=3,求cos x+sin x sin^3 x -cos^3 x sin^3 x -cos^3 x =(sin x -cos x )(sin^2 x +sin x*cos x +cos^2 x )问下这个是个公式还是什么?怎么样算出来的? 1/cos(x) - tan(x) = 3 求sin(x)1/cos(x) - tan(x) = 3求sin(x) 如果f(cos x)=sin 3x,那么f(sin x)等于A.sin 3x B.-sin 3x Ccos 3x D-cos 3x sin（sin（sin（sin（x）=cos（cos（cos（cos（x）,X等于多少? cos x /sin x= 求证(3-sin^4 x-cos^4 x)/2cos^2 x=1+tan^2 x+sin^2 x Sin x-sin y=2/3 cos x-cos y=1/2 求cos(x-y) 关于sin^2x+cos^2x 的应用式子：cos^6x+sin^6x=（cos^2x+sin^2x)(cos^4x-cos^2xsin^x+sin^4x)=(cos^2x+sin^2x)^2-3sin^2xcos^2x 求这两步算法中的具体思路 ps:cos^2x=cosx的二次方 解方程：cos^3x-sin^3x=1 ∫cos^4x/sin^3x dx=? ∫sin(3x)cos(4x)dx= y =(cos^2) x - sin (3^x),求y'