4x^2+y^2-16x+12=0,设y=2sinθ,θ参数（化方程为参数方程）

设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y 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x大于1,y大于0,x^y+x^-y=2根号二,x^y-x^-y等于? 设实数x,y满足 x>=0 x-2y>=0 x-y-2 设x,y满足约束条件x>=0 x>=y 2x-y 设z={x-y x≥2y,x/4+y/2 x 设x,y满足10x^2-16xy+8y^2+6x-4y+1=0,则x-y=? 设x＞0y＞0,x≠y,x^2-y^2=x^3-y^3,求证：1＜x+y＜4/3 设x,y是有理数,并且x,y满足x^2+2x+y^2-4y+5=0求x+y的值 设y=(2+x)^x,(x>0) ,求dy 设变量X,Y满足约束条件{X-Y+3>=0,X+Y>=0,-2 设变量x,y满足约束条件:x-y+3>=0 x+y>=0 -2 设不等式组x+y-2>=0,x-3y+6>=0,x-y 设x>0,y>0,x+y=1,求8/x+2/y的最小值 设z=2x+y式中变量x,y同时满足x-4y 设f(x+y,x-y)=x^2-y^2,则f(x,y)=