设实数X,Y,A,B,满足X^2+Y^2=3,A^2+B^2=1,则AX+BY的最大值是?我的思路：X^2+Y^2=3-----------------------①A^2+B^2=1-----------------------②①+②得：X^2+Y^2+A^2+B^2=4X^2+A^2≥2XAY^2+B^2≥2YB所以,2XA+2YB≥4所以,AX+BY≥4但是,=

设实数x,y满足 x>=0 x-2y>=0 x-y-2 设实数x,y满足约束条件：x>=2;y>=x;2x+y 设x=a^2b^2+5,y=2ab-a^2-4a,若x>y.则实数a,b应满足的条件为? 设x=a²b²+5,y=2ab-a²-4a,若x>y,则实数a,b需满足什么条件? 设实数a.b.x.y满足a^2+ b^2=1,x^2 +y^2=3,则ax +by的最大值是多小 设实数x,y满足方程组①x-y-2=0 ③2y-3 已知实数a,b,x,y,满足不等式（a+b）(x+y)>2(ay+bx),求证（x-y）/(a-b)+(a-b)/(x-y)>=2 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= 设正实数x,y满足x^3+y^3=x-y,求证：x^2+4y^2 设Z=x+y,其中实数x,y满足不等式x+2y>=0,x-y 设z=x+y,其中实数x,y满足{x+2y>=0,x-y 设实数x,y满足x的平方+4y的平方+2x 设0,＜a＜b＜c,实数x,y(x＞y)满足2x+2y=a+b+c,2xy=ac,求x,y的取值范围 设实数x、y满足方程2x^2+3y^2=6y,求x+y的最大值 设实数x、y满足方程2x²+3y²=6y,求x+y的最大值 设实数x,y满足3 设实数x,y满足3