设f(x+y,x-y)=(x²-y²)/2xy ,则f(x,y)=?
设f(x+y,xy)=x^2+y^2,则f(x,y)
高数题 设f(x+y,x-y)=x^2-xy,则f(x,y)=多少
f(x+y,xy)=x^2+y^2
设函数f(x,y)=sin(x+y),那么f(0,xy)=( )
设(X,Y)的概率密度为f(x,y)=8xy,0
设函数Y=f(x)由方程xy+y^2-2x=0,则dy/dx=?
f(xy)=f(x)+f(y),证明f(x/y)=f(x)-f(y)
f(x+y,xy)=x²+y²,则f﹙x,y﹚=?函数z=2xy-3x²-3y²
设(X,Y)的概率密度为f(x,y)=x+y (0
函数f(x)定义域R且为增函数,f(xy)=f(x)+f(y)证明f(x/y)=f(x)-f(y)
设y=f(x)是可导函数,则y=f(1+x
设y=f(x^2-x),f二阶可导,求y的二阶导数