记F(x,y)=(x-y)^2+(x/3+3/y)^2,(y≠0),则F(x,y)的最小值是A,12/5 B.16/5 C,18/5 D,4

已知f(x)=3^x,求证：(1)f(x)·f(y)=f(x+y);(2)f(x)/f(y)=f(x-y). f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? 设f(x+y,x-y)=x^2-y^2,则f(x,y)= 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= 已知f(x+y,y/x)=x^2-y^2,则f(x,y)= f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! f(x+y,y/x)=x^2-y^2求f(x,y) f(x+y,y/x)=x^2-y^2,求f(x,y),详见里面 f(x+y,x-y)=2xy(x-y),求f(x,y) f(x+y)=f(x)+f(y)+2xy f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y 高数题!f(x,y)=x^3-2xy+3y^2,求f(x+y,x-y).要借题步骤 函数f定义在有序正整数对的集合上,且满足下列性质：（1）F(x,x)=x; (2)F(x,y)=F(y,x) ;(3)F(x,x+y)=x+y/yF(x,y),求F(2010,2011).;(3)F(x,x+y)=（x+y）除以y再乘以F(x,y) (X,Y) f(x,y)={12y^2,0 f(x+Y)+f(x-y)=2f(x)f(Y) 求其是偶函数 急 求证f（x+y）+f(x-y)=2f(x)f(y)是周期函数 对任意的实数x,y,f(x+y)=2f(y)+x^2+2xy-y^2+3x-3y,求f(x) 已知F(X+Y,X-Y)=X^2*Y+X*Y^2,则F(X,Y)=?