x²+y²-4x+2my+2m²-2m+1=0x²-4x+4+y²+2my+m²=-2m²+2m-1+4+m²(x-2)²+(y-m)²=-m²+2m+3-m²+2m+3＞0m²-2m-3＜0(m+1)(m-3)＜0-1＜m＜3
m=3或者-1
