c=2√5/2=√5
x^2/a^2-y^2/b^2=1
a^2+b^2=c^2=5
b^2=5-a^2
代入点(3,2)
3^2/a^2-2^2/(5-a^2)=1
a^2=3
b^2=c^2-a^2=2
双曲线方程为x^2/3-y^2/2=1