焦点在y轴
c=5
y^2/b^2-x^2/a^2=1
x^2/m^2+y^2/n^2=1
n>m
n^2=m^2+5^2
P在椭圆上
所以9/m^2+16/(m^2+25)=1
9(m^2+25)+16m^2=m^2(m^2+25)
m^4=9*25
m^2=3*5=15
n^2=40
椭圆x^2/15+y^2/40=1
渐近线y=±(b/a)x
P在渐近线上
4=(b/a)*3
b=4a/3
a^2+b^2=c^2=25
25a^2/9=25
a^2=9,b^2=16
y^2/16-x^2/9=1