设f(x+y,x-y)=x^2+y^2-x*y求f(x,y)

设f(x+y,x-y)=x^2-y^2,则f(x,y)= 设f(x+y,x-y)=x^2+y^2-x*y求f(x,y) 设f(x+y,x-y)=x^2+xy,求f(x,y) 设f(x)=e的y次方,证明：（1）,f(x)f(y)=f(x+y) ,(2),f (x)/f(y)=f(x-y) 设f（x+y,xy）=x^2+y^2,则f（x,y） 一道多元函数问题.设f(x-y,y/x)=x^2-y^2,则f(x,y)=? 设f(x+y,x-y)=x^2-y^2,则函数f(x,y)= 设随机变量(X,Y)的概率密度为f(x,y)={2-x-y,o 设随机变量(X,Y)的概率密度为f(x,y)={2-x-y,o 设随机变量(X,Y)的概率密度为f(x,y)={2-x-y,o 设y=f(x),f'(x)存在,求y=f(2^x)的导数 设函数f(x,y)=xy/根号x^2+y^2,求limf(x,y)x,y趋于0 设f(x+y,xy)=x^2+y^2-xy,则（∂f(x,y)）/∂y= 设f(x+y,y/x)=x^2+y^2,则f(x,y)=?,f(x-y,xy)=? 设函数f(xy,x+y)=x^2+y^2+xy,求∂f(x,y)／∂x和∂f(x,y)／∂y 设f(x,y)=e^(x^2+y^2) 则 f（x,kx）=? 高数题 设f（x+y,x-y）=x^2-xy,则f(x,y)=多少 设函数f(x,y)=(x-y)/(x+y),求函数f(x,y)在x=0,y=2的全微分