把y=kx+m代入x^2/3-y^2=1得x^2-3(k^2x^2+2kmx+m^2)=3,整理得(1-3k^2)x^2-6kmx-3m^2-3=0,1-3k^2≠0,△/4=9k^2m^2+(1-3k^2)(3m^2+3)=3m^2+3-9k^2>0,∴k^2≠1/3,m^2>3k^2-1,①设M(x1,y1),N(x2,y2),则x1+x2=6km/(1-3k^2)...