第1个回答 2013-11-19
F1(-1,0),F2(1,0)
|F1F2|=2c=2
s=(1/2)*|F1F2|*|yA-yB|
4/3=(1/2)*2*|yA-yB|
|yA-yB|=4/3
AB:y=k(x+1)
x=(y-k)/k
x^2/2+y^2=1
[(y-k)/k]^2+2y^2=2
(1+2k^2)y^2-2ky-k^2=0
(yA+yB)=2k/(1+2k^2),yA*yB=-k^2/(12k^2)
(yA-yB)^2=(yA+yB)^2-4yA*yB
(4/3)^2=4k^2/(1+2k^2)^2+4k^2/(1+2k^2)
(k^2+2)*(k^2-1)=0
k^2=1
y=±(x+1)