F(XY,X-Y)=X2+Y2求F(X,Y)=?
求函数f(x,y)=x2+xy+y2-6x-3y的极致
已知实数x,y满足1≤x2+y2≤4,求f(x,y)=x2+xy+y2的最大值和最小值
求函数f(x,y)=(x2+y2)2-2(x2-y2)的极值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
正整数x,y满足x2-y2=2xy,求x-y/x+y的值
整数x,y满足x2-y2=2xy,求x-y/x+y的值
求二元函数F(x,y)=x2+y2+xy,在条件x+2y=4d的条件下的极值
正数xy满足x2-y2=2xy,求x+y分之x-y的值
若函数f(x)对任意实数x,y均有f(x+y)=2f(y)+x2+2xy-y2+3x-3y,则f(x)的解释式为____
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
f(xy)=xf(y)+yf(x) 求f(x)
f(xy)=f(x)+f(y),证明f(x/y)=f(x)-f(y)