设实数x,y满足x2+2xy-1=0,则x+y的取值范围是______.
(2008•杭州一模)设实数x,y满足x2+2xy-1=0,则x+y的取值范围是______.
设实数x,y满足x2+2xy-1=0,则x+y的取值范围是______.
已知x、y是实数且满足x2+xy+y2-2=0,设M=x2-xy+y2,则M的取值范围是______.
设实数x,y满足x2+y2=1则 xy的取值范围是?
设实数xy满足x2 +2y2=6,则x+y的取值范围
设x,y≠0,且方程(x2+xy+y2)a=x2-xy+y2成立,则实数a的取值范围是______.
已知实数x,y满足x2+y2=2x,则x2y2的取值范围是______.
设实数X,Y满足X^2+2XY-1=0,则XY的取值范围是?这个是对的
已知实数xy满足x2+y2-4x+3=0则(x+y-3)/(x-y+1)的取值范围是
已知实数xy满足x/y=x-y,且y>1,则实数x的取值范围是
若实数x,y满足2x2+3y2=1,S=3x2-2y2,则S的取值范围是______.
设x,y是实数,且 x2+xy+y2=3.那么,x2-xy+y2的取值范围是?