00:01
Here on this problem, we have this set of parametric equations.
00:03
We're already told it's a circle, but we want to answer some stuff from it.
00:08
One of the first things we want to talk about is what's going on whenever t is zero.
00:14
And so let's plug zero in for t in both spots and identify what we have going on.
00:19
The cosine of zero is one times four is four, so our x coordinates four.
00:26
The sign of zero is zero, and so our y coordinate is zero.
00:33
And so it means we're starting there at that point for zero.
00:36
So when t is zero, we're at the point four zero.
00:42
Now next thing i'm going to plug in here, let's plug in pi over six.
00:50
Now remember, you're multiplying it by three.
00:52
So whenever you take three times pi over six, that's really pi over two.
00:56
And so the value inside of here is really pi over two, because you're multiplying that t value by three.
01:02
The cosine of pi over two is zero.
01:05
And so our x -cordant in here is zero...