00:01
We want to write the equation of the ellipse with our vertices.
00:04
I'm just going to write v for vertices.
00:07
Those vertices are at negative 1, negative 9, and negative 1 -1.
00:21
Let's plot those two points.
00:25
So there's negative 1, and then 1, 2, 3, 4, 5, 6, 7, 8, 9.
00:34
So there's negative 1, negative 9, and negative 1, and negative 1, then the endpoints of the minor axis are negative 4 and negative 4 and then the other one is 2 negative 4 so 1 2 3 4 1 2 3 4 there's 1 and then 2 negative 4 will be here so that ellipse will look like this, notice that our center is the midpoint of the vertices.
01:23
It's also the midpoint of the endpoints of the minor axis.
01:28
And so our center here, when you add negative 4 plus 2, negative 2 divided by 2 is negative 1.
01:35
And if you look at the vertices, negative 1 plus negative 1 is negative 2 divided by 2 gives you negative 1.
01:42
Now let's get the y coordinate of the center.
01:44
Negative 9 plus 1 is negative 8 divided by 2 is negative 4 and if you look at the end points of the minor axis negative 4 plus negative 4 is negative 8 divided by 2 would be negative 4 so there's our center now we've got to find our a and b and a we usually let be the larger so for a we're going to count from the center to a point on the ellipse vertically.
02:16
So how many units do we have to count up and down? and it looks like five units.
02:25
Now our b will be how many units we have to count from the center horizontally to a point on the ellipse...