设X^2+2X-1=0.Y^4-2Y^2-1=0,且xy^2不等于1,求[（xy^2+y^2+1)/x]^1999的值

设x,y满足约束条件x+y>=1,x-y>=-1,2x-y 设x,y满足约束条件x+y>=1,x-y>=-1,2x-y 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 设z={x-y x≥2y,x/4+y/2 x 设f(x+y,x-y)=x^2-y^2,则f(x,y)= 设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 设y=xlnx/1+x^2, 设x、y满足{2x+y≥4,x-y≥-1,x-2y≤2,则z=x+y 设实数x,y满足2x+y≤4,x-y≥-1,x-2y≤2,则z=x+y的最大值为 设x＞0y＞0,x≠y,x^2-y^2=x^3-y^3,求证：1＜x+y＜4/3 设x,y满足x^2/4+y^2=1,则k=(x 设z=2x+y式中变量x,y同时满足x-4y 设x>0,y>0,x+y=1,求8/x+2/y的最小值 设变量x y满足约束条件x-y≥-1 x+y≥1 2x-y≤1 z=(x-2y)/(x+y)的最大值 设实数X,Y满足2X+Y-2>=0,X-2Y+4>=0,3X-Y 设实数x,y 满足x²+4y²+2x-4y+2+0 则x+y= 设X,Y满足条件x-y+2>=0,x+y-4>=0,2x-y-5 设正实数x,y满足x^3+y^3=x-y,求证：x^2+4y^2