00:01
Here, we're given an equation and we're asked to find, well, rather we're given in a graph, and we're asked to find the equation of it.
00:07
Now, it oscillates, so that tells me it has to be a sign or a cosine.
00:12
And honestly, it doesn't matter which one you want to choose here.
00:16
I'm going to choose a cosine simply because it looks like it just goes flat at the bottom.
00:23
So i think it's going to have a nicer equation for a cosine.
00:25
But if you want to write it as a sign, that's just fine.
00:27
So i'm going to say y is equal to a times the cosine of, let's call it b times x minus c plus d.
00:38
Now if you use different variables here in your equation, that's just fine.
00:42
It doesn't make any difference.
00:44
Let's first, i like to find d.
00:46
D is the easiest one to start with because it's the center.
00:50
You can find that however you want to do.
00:52
I like to just kind of eyeball it.
00:54
Let's just say, okay, that looks like the center is there.
00:57
The next step, is a.
01:02
And here's where you get to confirm, did i get d right? because a is just the center to the maximum.
01:07
What's the distance from here to there? one, two, three, four, five.
01:12
So i got a is five...