00:01
Here we have the integral from pi over 7 to pi of the cosine of x, absolute value.
00:06
And we want to calculate that.
00:08
Well, let's first look at what is the absolute value of cosine look like.
00:12
So if i have cosine, it looks something like this, where this is 2 pi, this is pi over 2.
00:26
And so really, it's positive up until pi over 2.
00:30
Well, pi over 2 is a lot bigger than pi over 7.
00:33
So up until pi over 2, it's just the same.
00:37
It's just cosine.
00:38
So i'm going to say this is the integral from pi over 7 to pi over 2 of cosine of x.
00:47
Plus, well, actually i'm going to do a minus and we'll talk about that in a minute, the integral from the next region.
00:54
That's going to be from pi over 2 up until pi of my cosine of x.
01:00
Now why did i put a minus sign there? because i'm going to get a negative number here...