00:01
All right, for this question, we start with a point x, y, and we're told that the polar coordinates for that point are r and theta.
00:15
And it wants to know a few things about a few other points.
00:19
The first point is the point minus x, y.
00:25
It has the same height and the opposite left, right.
00:30
And it wants to know what the polar coordinates of that are.
00:33
And hopefully if we look at these as right triangles, we'll see that the height in both cases or the y value of both cases are the same, and the x value in both cases are the same.
00:47
And so therefore, the length of the polar coordinate needs to also be r because the other dimensions are the same.
00:57
The angle, if we're looking just at that angle right there, that would be theta.
01:03
However, since we're putting our angles in terms of the positive x -axis, our polar coordinates for that point is going to be r and 180 degrees minus theta.
01:25
And so that's going to be the polar coordinates for minus x and y.
01:31
The next point they're interested in is minus 2x and minus 2y.
01:36
And that's going to be over here.
01:39
It's going to have twice the x value, twice the y value.
01:45
And using similar triangles, we should know that the distance is 2r...