Is this the topic?
If yes, the answer is B, √5.
Please ask questions. In case I do nothing.
PF 1=4a，PF2=2a，
F 1F2=2√5a=2c
∴ e=c/a=√5
Successful speech 1
Dear students:
Hello everyone!
Ducal said, "I think, therefore I am." If you are alive, you must show your existence and