Question

What are the foci of

Answer 1

@ehuman

Answer 2

im not familiar with foci

Answer 3

Here are the details
http://hotmath.com/hotmath_help/topics/ellipse.html

what you need to find is
(1) the center of the ellipse
(2) "c", the distance from the center to one of the focus points
c^2 = a^2 - b^2
where a^2 and b^2 are the denominators in your equation
\[ \frac{(x-h)^2}{a^2} + \frac{(y-k)^2}{b^2} = 1\]

Answer 4

You mean the location of each focus?

Answer 5

You have a = 13 and b = 12. You need the value of c. What is the relationship between these three for an ellipse?

Answer 6

If you like, you can watch Khan's explanation
http://www.khanacademy.org/math/algebra/conic-sections/conic_ellipses/v/foci-of-an-ellipse