c1^2=c2^2=13
x^2/a1^2+y^2/b1^2=1
x^2/a2^2-y^2/b2^2=1
a1=a2+4
(c1/a1)/(c2/a2)=a2/a1=3/7
a2=3a1/7
a1=3a1/7+4
a1=7
a2=3
b1^2=36
b2^2=4
椭圆:x^2/49+y^2/36=1
双曲线:x^2/9-y^2/4=1
2c=6√3,c=3√3
椭圆实半轴为a,双曲线实半轴为a’
a-a‘=4
c/a:c/a’=3:7
c=3√13
解得a=7,a‘=3
b²=a²-c²=49-27=22
b’²=c²-a‘²=27-9=18
椭圆方程:x²/49+y²/22=1
双曲线:x²/9-y²/18=1