00:01
Okay, so for this question, we're given cotangent of negative pi over 6, and we're asked to use reference angles to find the exact value.
00:14
So, let me use a coordinate plane so we can better visualize where negative pi over 6 would lie.
00:20
We have 0 here, negative pi over 2 here, which is negative 90 degrees, negative pi here, which is negative 180 degrees, negative pi here, which is negative 180 degrees, negative 3 pi over 2 here and a full clockwise circle would bring us back to negative 2 pi here.
00:43
So negative pi over 6 would lie somewhere in the fourth quadrant and the angle would simply look like this.
00:53
So this is negative pi over 6.
00:57
And this is the reference angle we're trying to solve for.
01:00
If you notice, the reference angle is simply the positive value of the angle here.
01:05
So the reference angle is simply pi over 6.
01:11
So our new equation is the cotangent of pi over 6.
01:21
Now, if you remember your unit circle, you can remember that cotangent is 1 over tangent...