Question

conic section ellipse help
http://i.imgur.com/8pZfi.png

it asks for c and d but I'm not sure where to start. Should I assume those points are foci?

Answer 1

You should start by replacing x and y with the ordered pairs they gave you. That will give you two equations with 2 variables. Solve the system for c and d.

Answer 2

okay I got C but for D I got sqrt(-3) is this fine?

Answer 3

You should not get an imaginary number. I'll run it through. Hang on.

Answer 4

What did you get for c?

Answer 5

25

Answer 6

me too. So let's plug that information in:
\[\frac{10^2}{625}+\frac{3^2}{d^2}=1\]
\[\frac{9}{d^2}=1-\frac{100}{625}\]
\[\frac{9}{d^2}=\frac{525}{625}\]
\[d^2=\frac{9(625)}{525}\]

Answer 7

oh oops I forgot to square the 25 haha..
Thank You!

Answer 8

yw