求证:sin(x-y)sin(x+y)/sin²xcos²y=1-cot²xtan

求证:sin(x-y)sin(x+y)/sin²xcos²y=1-cot²xtan 求证 cos*xcos*y + sin*xsin*y + sin*xcos*y + xin*ycos*x = 1 求证 sinˇ4X+sin²Xcos²X+cos²X = 1 谁能帮我解一下这道题(sin(x+y))/(sin x sin y) = cot y + cot x x=2(cot t),y=2(sin²t),用t表示dy/dx 求方程[xcos(x+y)+sin(x+y)]dx+xcos(x+y)dy=0的通解, 求证sin^2x+sin^2y-sin^2x*sin^2y+cos^2x*cos^2y=1 设y=sinx²+sin²x,求y' ∫sin²xcos³x dx 函数y=1-2sin²3x是 y=﹛sin[(1-lnx)/x]﹜²,求导 已知Y=sin^4*3xcos^3* 4x求Y的导数