问题
选择题
设双曲线的两条渐近线为y=±
|
答案
由题意可得,当焦点在x轴上时,
=b a
,∴1 2
=c a
=a2+b2 a
=a2+(
)2a 4 a
.5 2
当焦点在y轴上时,
=a b
,∴1 2
=c a
=a2+b2 a
=a2+(2a)2 a
,5
故选C.
设双曲线的两条渐近线为y=±
|
由题意可得,当焦点在x轴上时,
=b a
,∴1 2
=c a
=a2+b2 a
=a2+(
)2a 4 a
.5 2
当焦点在y轴上时,
=a b
,∴1 2
=c a
=a2+b2 a
=a2+(2a)2 a
,5
故选C.