cos x /sin x=

sin（sin（sin（sin（x）=cos（cos（cos（cos（x）,X等于多少? cos x /sin x= 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x y=2cos x (sin x+cos x) 已知sin(x)+3cos(x)=2,求sin(x)-cos(x)/sin(x)+cos(x)=? sin²x+cos²x= y=(sin x + COS x)^2 cos2x=cos^x-sin^x 为什么? sin(x/2)cos(x/2)= (1+cos x-sin x)/(1-sin x-cos x)+(1-cos x-sin x)/(1-sin x+cos x)=? 已知:tan x=2 求:sin x+cos x/sin x-cos x=? 函数f(x)=sin(x)+cos(x)-sin(x)*cos(x)的值域是什么 2sin^2x - 5sin x cos x=3 cos^2x,求X, f（x）=sin x +cos x +sin x * cos x ,求值域 sin^2 x-cos^2 x=cos 求导数:(cos x)'=－sin x 求导数:(cos x)'=－sin 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)