00:01
All right, they give us this equation up here, which actually isn't very interesting.
00:04
We could have done that.
00:05
That's the chain rule, right? derivative of sine x or sign anything is cosine, and then we multiply by derivative of the inside, which is pi.
00:15
Pi is a constant.
00:16
Okay, so that wasn't new information.
00:19
They do tell us that they want an anti -derivative of cosine pi -x, which means we want the derivative of big f to be cosine pi -x.
00:30
And then they wanted f, big f, of 3 over 2 to be 0.
00:37
Okay.
00:39
So let's see, we want the derivative to be cosine pi x.
00:44
So we can use this, i guess.
00:47
We can say we can divide both sides by pi or multiply by 1 over pi.
00:53
And that would mean 1 over pi times a derivative would be cosine pi.
01:00
And then this is a constant so it could go inside.
01:03
You don't really, it feels a little bit contrived to do this, but i'm just showing you now.
01:08
I'm getting this into the exact form.
01:12
And this is exactly the same as this is d by dx, big f of x, right? that's the same as f prime.
01:19
So i've created this exact thing where big f of x can be this thing.
01:27
And it's okay doing this a little bit.
01:32
But i can add any constant i want...