Find equation of Ellipse

[shawie]

without early morning tutorials and the site, i really don't know how i'm going to get through this class lol alright, here is a problem that i don't know how to answer:

The ellipse has its center at the origin. Find an equation of the ellipse.

Vertex (0,-13); Focus (0,-5)



oh now that i look at it again there's another problem i couldn't figure out:

The direction says- Sketch each ellipse. Label the center and vertices.
(x+7)^2+(y-5)^2 /9 =1

think I can figure out how to sketch it, if only I knew how to figure out how to find the major and minor axis and the foci points. help please?

 

[tkhunny]

without early morning tutorials and the site, i really don't know how i'm going to get through this class lol alright, here is a problem that i don't know how to answer:

The ellipse has its center at the origin. Find an equation of the ellipse.

Vertex (0,-13); Focus (0,-5)

You have to try a little harder.

If it's centered at the Origin, it looks like this x^2 / a^2 + y^2 / b^2 = 1

You have one Vertex (0,-13). This leads DIRECTLY to another vertex, (0,13)
You have one Focus (0,-5). This, with the previous information, leads to three things:
1) Focus and Vertex in the same direction?? Major Axis!!! b = 13
2) Another Focus is at (0,5)
3) c = 5

If you don't know what 'c' is, you need to go look it up. The relationship between a, b, and c will be your friend. It will help you find 'a'. What could be cooler than that?