函数f(xy,x+y)=x^2+xy+y^2,则df(x,y)=?
已知二元函数f(xy,x+y)=x^2+y^2,求f(x,y)
f(x+y,xy)=x²+y²,则f﹙x,y﹚=?函数z=2xy-3x²-3y²
求函数的表达式已知f(x,y)=xy/(x^2+y^2)则f(y/x,1)=?
多元函数概念习题 f(xy,x/y)=(x+y)^2 ,则f(x,y)=?
设f(x+y,xy)=x^2+y^2,则f(x,y)
f(x+y,xy)=x^2+y^2
已知df(x,y)=(2y^2+2xy+3x^2)dx+(4xy+x^2)dy,求f(x,y)
f(x)满足f(x+y)+f(xy)=2f(x)f(y)求函数的奇偶性
函数y=f(x)由方程xy^2+sinx=e^y,求y′
求函数f(x,y)=xy(2-x-y)的极值
求函数f(x,y)=x³+y³-3xy+2的极值
f(2x+y,2y+x)=xy,求f(x,y)