A1坐标是(-2,0),A2(2,0)设P坐标是(x,y)k(PA1)=y/(x+2),K(PA2)=y/(x-2)k(PA1)K(PA2)=y^2/(x^2-4)又有x^2/4+y^2/3=1x^2+y^2*4/3=4x^2-4=-y^2*4/3故K(PA1)*K(PA2)=-3/4而又有K(PA2)的范围是[-2,-1],(-3/4)/(-2)=3/8,-3/4/(-1)=3/4则有K(PA1)的范围是[3/8,3/4]