00:02
Okay, so the general parametric equations for the motion of this particle that's tracing an ellipse, and now notice that the minor, let's see the x radius is a and the y radius is b.
00:17
So here we have minus a, a, b, and minus b.
00:27
So here's our ellipse that will be tracing out.
00:32
So the general form of the parametric equations are x equals a cosine theta, y equals b, sign theta, for theta in between zero and two pi.
00:49
Now this traces out the ellipse exactly once counterclockwise.
00:56
Okay.
00:57
So that's actually b.
00:59
Okay, so.
01:01
But for a, if we want to go clockwise, we just want to make the argument negative, and that'll make us trace in the negative or clockwise direction.
01:11
So for a, we just want to say, cosine of minus theta, a times cosine of minus theta, y equals b, sine of minus theta...