00:01
In this question, we are going to parameterize a line segment using the so -called polar angle.
00:10
So the line segment in question is this one.
00:14
It goes from the four points on the x -axis to two point on the y -axis.
00:22
And the parameter they want us to use is the angle of theta over here.
00:33
So how are we going to do this? well, in this case, i believe it is easiest to try and figure this out using a picture.
00:51
So from this drawing, we can tell that since this here is y and this here is x, we can tell that the tan of theta equals by definition of tangent y over x.
01:09
So we want to solve for x and y in terms of theta.
01:16
So we need some relation between x and y.
01:18
Thankfully we know this because this is a line.
01:23
So we can write y equals a x plus b.
01:28
We just need to figure out what the a and the b are.
01:31
Well the b is easy because we know the value of y when x equals 0.
01:38
So b equals 2.
01:41
Now how do we figure out a? well, when x increases by 4, y decreases by 2.
01:50
So a equals minus 2 divided by 4 or minus 1 1â2...