△≥0所以(2m-1)²-4m²≥0-4m+1≥0m≤1/4x1+x2=-2m+1x1x2=m²x1²=x2²所以x1=x2或x1=-x2若x1=x2则△=0,所以m=1/4若x1=-x2,x1+x2=-2m+1=0,m=1/2,不符合m≤1/4所以m=1/4