f(x,y)={2-x-y,0

(X,Y) f(x,y)={12y^2,0 已知f(0)=1,f(x-y)=f(x)-y(2x-y+1),求f(x) 已知：f(x+y)+f(x-y)=2f(x)*f(y),x.y取任何实数且f(0)不等于0,求证：f(x)为偶函数 f(x+y)=f(x)+f(y)+2xy f(x+y)+f(x-y)=2f(x)f(y) 求证：f(0)=1 f(x,y)={2-x-y,0 概率密度f(x,y )=2-x-y 0 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(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y 已知函数f(x)满足f(x+y)+f(x-y)=2f(x)×f（y）,且f(0)≠0,证明f(x)是偶函数 导数：f(x+y)=f(x)f(y),且f'(o)=1,求f'(x)f(x+y)=f(x)f(y),且f'(o)=1,求f'(x)f(x+y)=f(x)+f(y)+2xy,且f'(o)存在,求f'(x) f(1+x)=af(x),且f'(0)=b,求f'(1) f(x+y)=f(x)-f(y),那么f(-x)=f(0)-f(-x)=-f(-x).2f(-x)=0?