00:01
So let's do some analysis of negative pi over four.
00:04
And let me kind of try to draw a circle.
00:08
That wasn't very good, but we're not going to redo it.
00:11
And let's get to negative pi over four.
00:14
So negative pi over four, we know we're rotating down here.
00:19
And we know that this negative pi over four for our angle, we know that that's equivalent to negative 45 degrees.
00:28
And we know that this is one.
00:31
We know that the x coordinate on the unit circle is positive square root of 2 over 2, and we know that the y coordinate on the unit circle is negative square root 2 over 2.
00:43
So let's find the cosine of negative pi over 4, and that is the x coordinate.
00:55
Let's find the co -sicant of negative pi over 4.
01:00
And the co -sicant is the reciprocal of sign.
01:04
So i know i need to reciprocate this value.
01:08
Now we can't leave it in that form, though.
01:11
We can't leave it as negative 2 over the square root of 2...