x+y-1>=0,x-y+1>=0,4x+y-2>=0.实数x,y满足约束条件,求x-y/x+y取值范围

X>0 Y>0证1/x+1/y>=4/(x+y)X>0 Y>0 证1/x+1/y>=4/(x+y) x>0 y>0 x+y=1,4/X+9/y最小值x>0 y>0 x+y=1,求4/X+9/y最小值 {4x-3y-10=0 3x-2y=0,{3x-4(x-y)=2 2x-3y=1,{2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 设x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 4x+y-9>=0 ,x-y-1 先化简再求值; 解方程组 x(x-y)-y(x+y)+2xy 其中x=2 ,y=-22.x[x-x(x-1)],其中x=-2解方程组4x+3y=12x-y=32.y+1=2x 4x-y=2 3.2x+2y=0 2x-y+24=0 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}] 若x,y满足约束条件,x>=0,y>=0,x-y>=-1,3x+4y x>0 y>0 x+y=1 证(x+1/x)(y+1/y)≥25/4 证明：若x>0,y>0,x+y=1,则（x+1/x)(y+1/y)≥25/4 x,y>0,且x+2y=1,u=(x+1/x)(y+1/(4y)最小值是: x²-4x-1=0,求(2x-3)²-(x+y)(x-y)-y² x>0 y>0 x+y=1,4/X+9/y最小值 x>0 Y>0x+y=2求1/x+4/y的最小值 x^2-x+y^2+2y+5/4=0 求x^-1+y^0 解下列方程组：{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0