问题
填空题
椭圆
|
答案
∵方程2x2-x=0的根是:0,
.1 2
∴椭圆
+x2 3
=1的离心率是y2 k
,1 2
①焦点在x轴上时,a2=3,b2=k,c2=3-k,
e=
=c a
=3-k 3
,∴k=1 2 9 4
②焦点在y轴上时,a2=k,b2=3,c2=k-3,
e=
=c a
=k-3 k
,∴k=41 2
∴k=4或9 4
故答案为:4或9 4
椭圆
|
∵方程2x2-x=0的根是:0,
.1 2
∴椭圆
+x2 3
=1的离心率是y2 k
,1 2
①焦点在x轴上时,a2=3,b2=k,c2=3-k,
e=
=c a
=3-k 3
,∴k=1 2 9 4
②焦点在y轴上时,a2=k,b2=3,c2=k-3,
e=
=c a
=k-3 k
,∴k=41 2
∴k=4或9 4
故答案为:4或9 4