00:01
G of x equals x minus 2 sine x.
00:14
Taking the derivative 1 minus 2 cosine of x.
00:25
Set that to equal to 0, and we get negative 2 cosine x equals negative 1.
00:39
Cosine of x is 1 half.
00:44
Looking at a unit circle, the cosine of x will be 1⁄2.
00:50
Here and here and here.
00:56
Whoops.
00:57
Nope, not all those spots.
00:59
Let's go back here and here.
01:03
Now what is our interval here? negative 2 pi to positive 2 pi.
01:18
Okay.
01:20
Um, that would be pi over 3.
01:27
The critical points would be at this one is pi over 3.
01:35
This one down here is negative pi over 3.
01:42
And then we can also add, let me think, 2 pi, negative 2 pi.
02:05
Yeah, we would get the other one if we subtract 2 pi.
02:10
So 2 pi minus pi over 3, which would be 6 pi over 3 minus pi over 3, over 3.
02:30
So we also have 5 pi over 3 and negative 5 pi over 3.
02:39
Okay...