把直线代入x^2+3y^2-3=0
4x^2+6mx+3m^2-3=0
x1+x2=-3m/2
y1+y2=x1+m+x2+m=-3m/2+2m=m/2
因为中点坐标是x=(x1+x2)/2,y=(y1+y2)/2
所以x/y=(-3m/2)/(m/2)=-3
x+3y=0
直线和椭圆有交点则4x^2+6mx+3m^2-3=0有解
判别式=36m^2-48m^2+48>=0
m^2