4x^2+3y^2=48x^2/12+y^2/16=1a^2=16,b^2=12,c^2=16-12=4焦点为：(0,2),(0,-2)点(-5/3,-2)到(0,2),(0,-2)的距离和=√[(-5/3)^2+(-2-2)^2]+5/3=√(25/9+16)+5/3=13/3+5/3=6a=6/2=3b^=a^2-c^2=9-4=5椭圆标准方程:x^2/5+...