设|X-2|+(Y+1/4)^2=0,试求代数式X^2(X^2-XY+Y)-X(X^3-2X^2Y+XY-1)还有一题：（-2XY）^3·(X的平方乘Y-XY^2-1)=?

设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 设y=ln(1-2x),则y''(0). 设y=ln(1+2x),则y(0) 设y=ln(1-2x),则y''(0)... 设x＞0y＞0,x≠y,x^2-y^2=x^3-y^3,求证：1＜x+y＜4/3 设x>0,y>0,x+y=1,求8/x+2/y的最小值 设实数X,Y满足2X+Y-2>=0,X-2Y+4>=0,3X-Y 设X,Y满足条件x-y+2>=0,x+y-4>=0,2x-y-5 设实数x,y 满足x²+4y²+2x-4y+2+0 则x+y= 设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 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y=xlnx/1+x^2, 设x∈[0,π],y∈[0,1],试求函数f(x,y)=(2y-1)sinx+(1-y)sin[(1-y)x]的最小值. 设随机变量X,Y相互独立,且E(X)=E(Y)=0,D(X)=D(Y)=1,试求E[（X+Y）^2]. 设x,y满足x^2/4+y^2=1,则k=(x 接着提问数学题!设x>0,y>0,求证1/2(x+y)^2+1/4(x+y)>=√xy(√x+√y) 设x,y满足10x^2-16xy+8y^2+6x-4y+1=0,则x-y=?