若实数x,y满足x2+4y2=4x,则S=x2+y2的取值范围是______.
若实数x,y满足x2+4y2=4x,则S=x2+y2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______.
已知实数x,y满足x2+y2=2x,则x2y2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______.
已知实数x,y满足x2+y2=4,求x+y的取值范围
设实数x,y满足x2+y2=1则 xy的取值范围是?
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+y2-4x+1=0,求2x+y的取值范围?
若实数x,y满足3x2+2y2=6x,则x2+y2的最大值为______.
设实数xy满足x2 +2y2=6,则x+y的取值范围
已知实数x.y满足x2+y2=4.则3x+4y的取值范围是
若方程x2+y2+4x-2y+5m=0表示圆,则实数m的取值范围是______.