完成下列数学题÷(1/2xy^2 x^4y^3→→→→→→( ) -6x^2y^2z→→→→→( ) 1/3xy^4z^
求下列各极限 lim(x,y)→(0,1) (2-xy)/(x^2+2y)
5yz/(y+z)=6,4xy/(z+x)=3,3xy/x+y=2
初一 下 数学 1、已知3x-4y-z=0,2x+y-8z=0,求 x²+y²-z²÷xy
一道数学题,已知x+y+z=1,x^2+y^2+z^2=2,问xy+yz+zx,x^3+y^3+z^3
三元二次方程组(XY+X)/(X+Y+1)=2(XZ+2X)/(X+Z+2)=3(Y+1)(Z+2)/(Z+Y+3)=4
求极限lim(x,y)→(+∞,+∞) [(xy)/(x^2+y^2)]^xy.
求下列函数的偏导数 1)z=x^3*y^2 2)z=x^4+y^3 3)z=e^(xy)+yx^2 4)u=x^(z/y
已知三个数x,y,z,满足xy/x+y=-2,yz/y+z=4/3,zx/z+x=-4/3,求(xyz)/(xy+yz+
已知实数x,y,z满足x²-6xy+10y²+4y+|z²-3z+2|+4=0,求(x+y
设正实数x,y,z满足x^2-3xy+4y^2-z=0,则xy/z取得最大值时,2/x+1/y+2/z的最大值为
(3/4x^3y^3z^3-1/3x^2y^2z+1/2xy)/1/12xy
已知3x-y+2z=x+2y+3z=0,求(3x^-xy+2y^)/(2x^+4xy+y^)值?