先化简再求植:0.5(x+y+2)＾+0.5(x-y-2)(x-y+2)-2(x+y)其中x-y=6,xy=21

先化简再求植:0.5(x+y+2)＾+0.5(x-y-2)(x-y+2)-2(x+y)其中x-y=6,xy=21 mathematica软件,已知y[x],Y=f1(x),X(x)=f2(x),如何plot Y[X]?y[x_] := x + 9.81/2*x*xk=1X[x] = x - k*y'[x]/(1 + (y'[x])^2)^0.5Y[x] = y[x] + k/(1 + (y'[x])^2)^0.5Plot[{y[x],Y[X],},{x,0,2}] 已知|3x+y-0.5|+(x+2y+1.5)^2=0,求代数式（x-y)(x-2y)-3x(1/3x-y)+(2x+y)(2x-y) 快. 已知x>=0,y>=0,求证0.5(x+y)^2+0.25(x+y)>=x√y+y√x (x-y)(x+xy+y)+xy(y-x) 其中x=7.1 y=2.92x+y=0,2x-y=0.5,求2x^2-1/2y^2 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y (X,Y) f(x,y)={12y^2,0 x*x+2x+y*y-4y+5=0 x= y= 设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y [(2x+y)(2x+y)-(2x+y)(2x-y)]÷2y-0.5y 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 （x+3y)²-2（x-y)（x+y)+(x+y)²其x=0.5,y=-2 x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 【就一部不懂】如果x、y∈R,且x≠y,比较(x2+y2)2与xy(x+y)2大小作差法 (x2+y2)2-xy(x+y)2 =x＾4+y＾4+2x＾2y＾2-x＾3y-2x＾2y＾2－xy＾3 =(x-y)(x＾3-y＾3) =(x-y)＾2[(x+y/2)＾2+3y＾2/4] ∵x≠y (x-y)＾2＞0,(x+y/2)＾2+3y