00:01
For this problem, we are doing a series of graphs of some different parametric equations.
00:07
We are following a jet.
00:09
It has a speed of 0 .8 units per second.
00:12
In other words, that's mock .8.
00:15
We are going to show what the sound wave patterns look like at different points of time as the jet moves.
00:24
So our first graph, you can see this is the first one listed on the left hand side.
00:28
We are starting at the origin and we have gone five seconds.
00:33
So if you look back at exercises 49 and 50, we talked about what the parametric equations are for the different sounds emanating at different places at different times.
00:46
So from the origin, it's going to be t is the coefficient.
00:51
That tells me how many seconds have elapsed.
00:53
So in this case, it's five.
00:54
So five is a coefficient, cosine t and sign of t.
00:58
So that's a circle centered right around the origin.
01:02
My second one is at four seconds.
01:05
So instead of having a five as a coefficient, i have a four.
01:08
And it's not starting at the origin.
01:11
It's starting from the point, 0 .80...