2a=PF1+PF2=6 a=3
PF1垂直PF2,所以F1F2^2=PF1^2+PF1^2=(4/3)^2+(14/3)^2=212/9
F1F2^2=(2c)^2=4c^2=212/9
c^2=53/9
b^2=a^2-c^2=3^2-53/9=(81-53)/9=28/9
椭圆X^2/9+9Y^2/28=1
2a=PF1+PF2=6 a=3
PF1垂直PF2,所以F1F2^2=PF1^2+PF1^2=(4/3)^2+(14/3)^2=212/9
F1F2^2=(2c)^2=4c^2=212/9
c^2=53/9
b^2=a^2-c^2=3^2-53/9=(81-53)/9=28/9
椭圆X^2/9+9Y^2/28=1