f(x-y,xy)=x2+y2f(x-y,xy)=x2+y2 求f(x.y)

f(x-y,xy)=x2+y2f(x-y,xy)=x2+y2 求f(x.y) 已知f(xy,x-y)=x2+y2, F(XY,X-Y)=X2+Y2求F(X,Y)=? 设函数Z=f(x,y)=xy/x2+y2,则下列个结论中不正确的是（）A f(1,y/x)=xy/x2+y2 B f(1,x/y)=xy/x2+y2 C f(1/x,1/y)=xy/x2+y2 D f(x+y,x-y)=xy/x2+y2为什么选D,求详解 求函数f(x,y)=x2+xy+y2-6x-3y的极致 因式分解x2+y-xy-x (x-y)(x2+xy+y2) (x+y)(x2-xy+y2) 已知函数满足对任意xy属于R都有f(x+y)=f(x)*f(y)-f(x)-f(y)+2成立,且x2,证明x f(x+y)=f(x)+f(y)+2xy 对任意的x,y都有f(x+y)=2f(y)+x2+2xy-y2+3x-3y求f(x)表达式 f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y f(xy)=f(x)+f(y),证明f(x/y)=f(x)-f(y) f(x,y)=xy+e^x x arctanx/y ,求f(x+y,x-y) XY（XY-X2)乘以------------X-Y 已知f(x,y)=x2+y2,求f(x-y,√xy)第二题是：f(x-y,√xy)=x2+y2,求f(x,y)最好告诉下我为什么这么设. f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! f(x+y,x-y)=2xy(x-y),求f(x,y)