1.a = 6,e = 根号(2/3),1 - (b/a)^2 = 2/3,b^2 = a^2 / 3 = 12,x^2 / 36 + y^2 / 12 = 1
2.|PF1| + |PF2| = 2a = 6,|PF2| = 2,F1F2 = 2根号(7),cos
1.a = 6,e = 根号(2/3),1 - (b/a)^2 = 2/3,b^2 = a^2 / 3 = 12,x^2 / 36 + y^2 / 12 = 1
2.|PF1| + |PF2| = 2a = 6,|PF2| = 2,F1F2 = 2根号(7),cos