This is the same problem for me
I find the same values of:
Foci: + and - (sqrt(10), 0)
Directrices: + and - 5*sqrt(10)/2
Vertices: (5,0) (-5,0) (0, sqrt(15)), (0, -sqrt(15))
I only worry about the PF=ePd part of the question.
Does not this mean P * F = e * P * d?
When I am putting all of the numbers in the equation then the two sides are not being equal. My answer is:
(5 * sqrt(10) = sqrt(10)/5 * 5 * 25/sqrt(10)
so that (5 * sqrt(10) = 5 * sqrt(10)/2
When I look at the above link, they are using different equations (where do they find this?) and the answers result differently. They use
PF = a-ae =
and ePd = e(a-ae)/e =
This is not like I have. How must I find "PF =a-ae" and "ePd=e(a-ae)/e"? It is not in my book and I am not finding it on the internet.
My sides don't balance. The sides of him balance!
Hope someone is not busy to help me!