00:01
Okay, to integrate this, we're going to use u substitution, so u should be the angle 2x, and the du then would be 2.
00:10
Dx.
00:10
So let's rewrite our problem here.
00:15
I'm going to say this is a cosine of u, and we have to match up with the du.
00:22
We have the dx, we need the 2.
00:25
You can put the 2 in if you put a 1 -half out front.
00:29
So now the problem is 1 half the integration from 0 to pi over 4 of cosine of u and that is the du the integration of cosine is sign, so sign of we're going to take the u bot and put the 2x back in and that allows us to keep our integration values the same so this will be the sign of 2 times pi over 4 minus the sign of 2 times 0.
01:08
2 times pi over 4 would be 2 pi over 4 or pi over 2 minus sign of 0.
01:16
Now we could use our sign graph to help us here.
01:22
Pi over 2 is here, so this value is 1.
01:28
Let me mark down everything else here...