椭圆焦点在y轴
半焦距 = 根(25-16) = 3
设双曲线方程为 y^2/(9-a^2) - x^2/a^2 = 1
(1,5/2)代入得:
25/4 / (9-a^2) - 1/a^2 = 1
解得a^2 = 4
双曲线方程 y^2/5 - x^2/4 = 1
椭圆焦点在y轴
半焦距 = 根(25-16) = 3
设双曲线方程为 y^2/(9-a^2) - x^2/a^2 = 1
(1,5/2)代入得:
25/4 / (9-a^2) - 1/a^2 = 1
解得a^2 = 4
双曲线方程 y^2/5 - x^2/4 = 1