设实数x,y满足x2-2x|y|+y2-6x-4|y|+27=0,则y的取值范围是_.
问题描述:
设实数x,y满足x2-2x|y|+y2-6x-4|y|+27=0,则y的取值范围是______.
答
当y≥0,方程变为:x2-2(y+3)x+y2-4y+27=0,∵△≥0,△=4(y+3)2-4(y2-4y+27)=8(5y-9)≥0,∴y≥95.当y<0,方程变为:x2+2(y-3)x+y2+4y+27=0,∵△≥0,即△=4(y-3)2-4(y2+4y+27)=8(-5y-9)≥0,∴...