求证sin^2x+sin^2y-sin^2x*sin^2y+cos^2x*cos^2y=1

求证cosx-cosy=-2sin （x+y/2）*sin （x-y/2） 求证sin^2x+sin^2y-sin^2x*sin^2y+cos^2x*cos^2y=1 求证sin²x-sin²y=sin(x+y)sin(x-y) 化简sin(2x-y)*sin y+cos(2x-y)*sin y 求证 cos*xcos*y + sin*xsin*y + sin*xcos*y + xin*ycos*x = 1cos*xcos*y + sin*xsin*y + sin*xcos*y + sin*ycos*x = 1注意：[*] 的意思是 [ ^2 ]写下左右过程.. y=[sin^2(x)]*[sin^2(x)]求导 一道三角恒等式证明题请证明sin(x+y)sin(x-y)=sin^2(x)-sin^2(y) 求y=sin[sin(x^2)]的导数 证明tan^2x=2*tan^2y+1,求证sin^2y=2sin^2x-1 tan方x=2tan方y+1,求证sin方y=2sin方x-1 3sin^2x+-2sin^2y=2sinx sin^2x+-sin^2y=? 已知sinθ+cosθ=2sinx,sinθcosθ=sin²y,求证：4cos²2x=cos²2y sin(x^2)/sin^2x 求导 求证:(sin 2x /(1-cos 2x) )·(sin x /(1+sin x))=tan (π/4-x/2). y=(sin x + COS x)^2 三角等式求证：cos^6x+sin^6x=1-3sin^2x+3sin^4x 求证:sin^2/(sin-cos) - (sin+cos)/(tan^2 -1) =sin+cos 求证:sin(2α+β)/sinα-2cos(α+β)=sinβ/sinα