Question

One focus is at (5,-11.94). Find the other focus for the ellipse defined by this equation: (x-5)^2/1 + (y+4)^2/64=1

Answer 1

The ellipse is centered at 5,-4
The minor axis is 2a with a = 1
The major axis is 2b with b = sqrt(64) = 8.
Have to look up for the foci again.

Answer 2

so the major axis is 2 x 8 or is it just 8, thanks for the help btw

Answer 3

The foci are at sqrt(b^2 - a^2) = 7.937, have to compute the offsets based on the origin.

Answer 4

I think the terminology is major axis = 2 x 8
semi-major axis = 8

Answer 5

study up :)
http://en.wikipedia.org/wiki/Ellipse

Answer 6

:/

Answer 7

so how do i get the y value for the foci, the x being 7.937 right?

Answer 8

Offsets: foci are at x = 5
y-values are -4 +/- 7.937 = -11.937, 3.937

Answer 9

This ellipse has its long dimension vertical.

Answer 10

so its -11.937,3.937?

Answer 11

Those are the y's.
(5,-11.937) and (5,3.937)

Answer 12

Maybe I didn't say that clearly. Because the ellipse is oriented vertically (y stretched more), the foci have the same x-value, which is equal to the origin, 5.
The foci are +/- sqrt(63) see above
with respect to the y-value of the origin, which is -4, so that gives what I said.